Enhancing cutaneous delivery with laser technology: Almost there, but not yet

Journal Pre-proof Enhancing cutaneous delivery with laser technology: almost there, but not yet ´ Sergio del R´ıo-Sancho, Vanessa Castro-Lopez, Mar´ıa Jose´ Alonso

PII:

S0168-3659(19)30554-1

DOI:

https://doi.org/10.1016/j.jconrel.2019.09.014

Reference:

COREL 9941

To appear in: Received Date:

2 July 2019

Revised Date:

20 September 2019

Accepted Date:

23 September 2019

´ Please cite this article as: del R´ıo-Sancho S, Castro-Lopez V, Alonso MJ, Enhancing cutaneous delivery with laser technology: almost there, but not yet, Journal of Controlled Release (2019), doi: https://doi.org/10.1016/j.jconrel.2019.09.014

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier.

REVIEW

Enhancing cutaneous delivery with laser technology: almost there, but not yet

Sergio del Río-Sanchoa, Vanessa Castro-Lópeza, María José Alonsoa,b,c,* a

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The use of laser technology is well-established in medical practice Ablative lasers show potential for delivering biologics in preclinical research Clinical trials with ablative lasers focus on the delivery of small molecules The value of pressure wave-assisted cutaneous drug delivery has been underestimated New laser devices will revolutionize cutaneous drug delivery in the near future

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Highlights

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Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Av. Barcelona s/n, Campus Vida, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Spain bDepartment of Pharmacy and Pharmaceutical Technology, School of Pharmacy, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain c Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain. ⁎ Corresponding author at: CIMUS Research Institute, Av. Barcelona s/n, Campus Vida, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Spain. E-mail address: [email protected] (M.J. Alonso). Graphical abstract

0. Abstract Preclinical research has shown the potential of different laser-based strategies (direct ablation, photothermolysis and mechanical waves) to overcome the stratum corneum and facilitate the cutaneous delivery of drugs. However, specific protocols for the routine use of these strategies have not been stablished yet. The aim of this review has been to provide the readers with a view of the translational prospects of the different laser technologies with regards to their utility for enhancing the penetration of drugs.

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For this, we have comparatively analyzed the preclinical research disclosed for laser-assisted delivery of classical small molecules as well as new biologics with the studies performed at the clinical level. In addition, we present the future perspectives of laser technological developments considering the evolution of the global laser market.

Keywords: CO2 laser; Direct ablation; Er:YAG laser; Mechanical waves; Medical lasers; Photothermolysis.

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Abbreviations:

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5-FU: 5-fluorouracil; AA: ascorbic acid; AA2G: ascorbic acid 2-glucoside; AH: articaine hydrochloride; Al2O3: alumina; ALA: 5-aminolevulinic acid; ASOs: antisense oligonucleotides; ATG: antithymocyte gamma globulin polyclonal antibody; BAC: bacteriochlorin; BAS: basiliximab; BET: betamethasone; BETe: betamethasone esters; BonNT A: botulinum neurotoxin Type A; BUP: buprenorphine; CAL: calcipotriol; CAGR: compound annual growth rate; CIS: cisplatin; CLO: clobetasol propionate; CNTS: CaCO3 containers filled up by Fe3O4 nanoparticles; Cyt C: cytochrome C; DIC: diclofenac sodium; DNCB: dinitrochlorobenzene; DPCP: diphencyprone; EFF: delivery efficiency; Er:YAG: erbium-doped yttrium aluminium garnet; FD: fluorescein isothiocyanate labeled dextran; FITC: fluorescein isothiocyanate; FITC-BSA: fluorescein isothiocyanate labelled bovine serum albumin; fLP: fluorescent latex particles; fMS: fluorescent microspheres; FSH: follicle-stimulating hormone; FSI: fluorescence signal increase with respect to control; GEN: gentamicin; GFP: green fluorescent protein; HA: hyaluronic acid; HBsAg: hepatitis B surface antigen; HGF: hair growth factor; hGH: human growth hormone; HYD: hydroquinone; IMQ: imiquimod; IND: indomethacine; IngMeb: ingenol mebutate; INS: insulin; LID: lidocaine; LYS: lysozyme; MAL: methyl aminolevulinate; MAP: magnesium ascorbyl phosphate; MB: methylene blue; MM: molecule model; MDAI: maximum deposited amount increase with respect to control; MOR: morphine; MTFI: maximum transdermal flux increase with respect to control; MTX: methotrexate; MXD: minoxidil; NAL: nalbuphine; Nd:YAG: neodymium-doped yttrium aluminium garnet; OS2966: monoclonal IgG1 therapeutic antibody; P.L.E.A.S.E.: painless laser epidermal system; pAcGFP: DNA vector pAcGFP1-C1; pDNA: plasmid DNA; PEGs: polyethylene glycols; PEP: peptides; PLLA: poly-L-lactic Acid; PPT: podophyllotoxin; PRE: prednisone; PRP: platelet-rich Plasma; PSP: red-fluorescent polystyrene-particles; PTX: pentoxifylline; QDs: nanocrystal quantum dots; RAP: rapamycin; RD70: rhodamine B-labeled dextrane 70 kDa; SC: stratum corneum; siRNA: small interfering RNA; rb-bFGF: recombinant bovine basic fibroblast growth factor; SRB: sulforhodamine B; SSG: sodium stibogluconate; TA: triamcinolone acetonide; T-IgG: TRITC-conjugated Goat Anti-Mouse IgG; TiO2: titanium dioxide;

TR-OVA: texas Red-ovalbumin; TRE: tretinoin; TXA: tranexamic acid; Vit E: D-α-tocopherol succinate.

1. Introduction

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Human skin is a remarkably efficient barrier against the cutaneous penetration of xenobiotics. The stratum corneum (SC) is the outermost skin layer, composed of only 10-30 layers of keratinocytes which is considered to be the major barrier for drug absorption [1-5]. Due to the inherent properties of the SC, the Lipinski´s rule of five used to predict optimal drug candidates for oral delivery does not apply well for transdermal permeation of active compounds [6, 7]. In fact, the ideal characteristics for optimal passive diffusion through the SC were reported to be low molecular weight (<500 Da), moderate lipophilicity (logPoct -1 to 4), low melting point, high aqueous solubility and high pharmacological potency [6, 8-11].

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The global market for transdermal drug delivery reached USD 4200 million in 2016, and it is estimated that it will reach the figure of USD 7358 million by the end of 2024 [12]. Psoriasis, eczema, skin cancer, pain management, cardiovascular diseases, neurological disorders, hormone replacement therapy, contraception, and smoking cessation are the main indications in this market [12, 13]. Unfortunately, the market has been limited to small drugs that can passively diffuse across the skin (i.e. percutaneous penetration enhancers, patches, gels, etc.) [14-16]. Several active transdermal delivery methods, including thermal and laser-assisted ablation, microneedles, iontophoresis, electroporation and sonophoresis have been developed [17-27], however, their exploitation is still very limited [13, 28, 29].

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In this regard, the global aesthetic laser market is anticipated to grow at a Compound Annual Growth Rate (CAGR) of 10.5% during the years 2018-2026 [30] which is expected to positively impact the use of laser for drug delivery purposes. This could be due to the more frequent application of medical lasers in different disease indications, the necessity of more efficacious treatments for skin diseases and the increasing demand in the use of non-invasive systemic administration of drugs [31, 32]. On the negative size, the strict safety regulations on the use of medical lasers and their cost may limit the exploitation of their full potential [33].

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Using laser technology to facilitate cutaneous delivery is not a new idea and has been previously covered by different reviews (i.e. [34-39]). However, in our understanding, previous reviews focus their attention on the medical lasers but not on the differences between preclinical and clinical trials in terms of the characteristics of the molecules evaluated (physicochemical properties, indication and dosage form) or on the endpoint of the experiment. In this review, after the presentation of the different medical lasers (section 2), the foremost exponent of each enhancement mechanism will be discussed in sections 3 to 5. Then, the use of laser technologies to facilitate cutaneous drug delivery based on preclinical and clinical evidences will be exposed (Fig. 1). Two different situations will be described: laser intervention in combination with drug treatments and laser-assisted enhanced drug delivery.

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Figure 1. Scheme of the structure of the review in sections 3 to 5. This figure was created with images adapted from Servier Medical Art by Servier. Original images are licensed under a Creative Commons Attribution 3.0 Unported License.

2. Medical lasers used in drug delivery

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Medical lasers (an acronym for Light Amplification by Stimulated Emission of Radiation [40]) are medical devices used to ablate the skin. The laser ablation is largely applied in aesthetics for the corrections of small skin imperfections such as dark spots or wrinkles and in clinics for the treatment of plantar warts, scars, or dyspigmentation among other uses. In addition, the possibility to remove the SC, which is the main barrier for drug delivery, is of high interest for the delivery of active ingredients.

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2.1. The beginnings of medical laser devices

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The scientific basis of laser goes back to Max Planck and Albert Einstein, at the beginnings of the 20th century. In 1900, Max Planck discovered the relationship between the energy and frequency of radiation and concluded that energy could be emitted/absorbed in the shape of “quanta”. Albert Einstein set the theoretical basis of the laser in 1916 [41]. However, it was not until 1960 that the first successful working laser was built by Theodore Maiman and fellow researchers at the Hughes Research Laboratories. This world´s first laser used a synthetic ruby crystal and was the first creation of coherent light [42, 43]. Dr. Leon Goldman, a pioneer in laser medicine in the 1960s, is considered the father of laser in dermatology. Charles Hard Townes, Nicolay Gennadiyevich Basov and Aleksandr Mikhailovich Prokhorov jointly received the Nobel Prize in Physics in 1964 "for fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle" [44]. In the same time period, other types of lasers were developed

for a variety of applications such as the Nd:YAG (neodymium-doped yttrium aluminium garnet), CO2 and Argon laser [43]. In the 1980s, more powerful and compacted lasers, such as the argon and Nd:YAG lasers, were developed and applied in dermatology, however, their utility was limited by the non-selective photothermal injuries they caused. In 1983, Rox Anderson and John Parrish introduced the term selective photothermolysis that revolutionized laser therapy [45]. Their findings demonstrated that the shorter the laser pulse width was, the higher its selectivity was. This selective skin thermal injury was found to be useful in the treatment of vascular, pigmented lesions as well as for tattoo and pigment removal. Two years later, in 1985, Strickland and Mourou firstly produced ultra-short pulses [46] (they were awarded the Nobel Prize in Physics in 2018 for this result). This result established a watershed in the drug delivery field because the lesions in the skin created by plasma-mediated ablation are more permeable to drug molecules.

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Later on, in the early 1990s, scanning technology was introduced for CO2 and Er:YAG (erbiumdoped yttrium aluminium garnet) lasers. This advancement translated into precise computerized control of laser beams [42]. Along these lines and complementing the previous innovation, Rox Anderson et al. introduced the new concept of fractional photothermolysis in 2004 [47] and the ablative fractional laser as a new drug delivery-enhancement technique in 2010 [48]. Dr. Anderson developed many of the non-scarring laser treatments currently used in clinical practice and his research has contributed to our understanding of human skin photobiology, laser based transdermal drug delivery, laser-tissue interactions, photodynamic therapy, optical diagnostics, mechanisms of drug photosensitization and tissue optics.

2.2. Structure and characteristics of medical lasers

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The components of the lasers (lasing material, pump source and optical cavity (Fig. 2)) determine the characteristics of the light emitted by the laser device (wavelength and energy) as well as the interaction with the surface irradiated [40, 49].

Figure 2. Schematization of the basic components of a laser.

The laser operates as follows: a pump source supplies input energy to the lasing material, thus exciting most of the electrons to a higher energy level (population inversion). As they decay back

to their original energy state, energy in the form of photons of light are released. If the direction of the emitted photons is parallel to the optical axis, they will be reflected between the reflectors (optical cavity) through the lasing material. Their energy will be amplified while they continue traveling in phase, at the same wavelength, and in the same direction until sufficient energy is reached to provoke a burst of laser light that will be transmitted through the partial reflector [40, 50-52] (Fig. 2).

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Furthermore, the wavelength of light emitted will depend on the lasing material of the laser, and it will affect the energy absorption. Wavelengths included are the ultraviolet (180-400 nm), visible (400-700 nm) and infrared region (700 nm-1 mm) and, as can be seen in Fig. 3, the different wavelengths absorb and excite different components of the skin, such as melanin or the water molecules, thus maximizing the damage/effect on the target tissue [53-56]. On the other hand, the laser energy depends on a combination of laser power (intensity) and pulse length. Low laser intensities (~1 W/cm2) over a long time (~1 second) causes photocoagulation, which leads to irreversible tissue damage; whereas lasers with high-intensity energies (1011 W/cm2) but ultra-short pulsed (10-12 seconds) lead to ablation with no thermal or mechanical damage to the non-targeted tissue [54, 57, 58].

Figure 3. Effect of the wavelength of light emitted on laser-tissue interaction. Figure adapted from [56].

2.3. Laser radiation in cutaneous delivery

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According to the structure of the laser beam and, therefore, the damaged area, it is possible to define two different laser conformations: full-beam and fractional beam. Full-beam lasers are based on damaging the whole targeted area which, on the skin, leads to delayed reepithelialization and erythema [45, 59]. In contrast, fractional beam lasers aim to damage several small areas at a specific depth within the selected target area (Fig. 4). This approach, on the skin, allows for a very short healing processes, a large diffusion area, and a more efficient delivery of drugs [47, 60, 61]. Moreover, and according to the structure and characteristics of the medical laser, the laser beam will interact with the surface irradiated by three possible mechanisms: photothermolysis, direct ablation or mechanical waves (Fig. 4) [36]. These interaction mechanisms and their use in cutaneous drug delivery will be discussed in depth in the following sections.

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Figure 4. Schematic of the different laser-assisted cutaneous delivery mechanisms. Photothermal effect (either full beam (A1) or fractional beam (A2)), direct ablation (either full beam (B1) or fractional beam (B2)) and mechanical waves (either by direct irradiation of a material (C1) or confined irradiation of a material (C2)).

3. Photothermolysis to enhance cutaneous delivery: the CO2 laser

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The photothermic effect is a consequence of the absorption of laser radiation by the water or other skin components, which finally results in heat production. This conversion of energy raises the temperature of the skin surroundings resulting, at the last stage, on small skin burns. Probably, the foremost exponent of this laser-skin interaction is the CO2 laser. Developed in 1964 by Patel and col. [62], its mechanism of action is based on vaporization and ablation [63]. The wavelength of the laser (10.600 nm) is strongly, but not exclusively, absorbed by the tissue water (absorption coefficient of ~800/cm), which provokes a loss of energy (Fig. 3) [64, 65]. Consequently, the energy employed for effective tissue ablation results in thermal damage to the skin (Fig. 4A) [66-68]. When superficially applied, the CO2 laser can cauterize small blood vessels achieving a dry wound. However, the CO2 laser is not able to cauterize large blood vessels, therefore, deep perforations may lead to severe bleeding [69]. In this sense, the

fractional beam application was seen to reduce the side-effects and the complication rates but does not avoid them entirely [70].

3.1. Current use of photothermolysis in medical practice (absence of drug)

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As shown in Table 1, the CO2 surgical laser is routinely used for small surgical interventions and for the treatment of different dermatological conditions. Important applications of this laser include those in the field of neurosurgery, where the creation of consistent incisions with limited zones of edematous tissue for the removal of central lesions or tumors is required [71-73]. Moreover, CO2 laser surgery dominates in interventions and surgeries where blood loss is significant since the CO2 cauterization properties were found having significant impact in: reducing the bleeding on large excisions sites [74-76], the extirpation of highly vascular tumors (such as superficial airway hemangiomas or angiokeratomas) [77-79], and interventions of malignant tumor diseases, where the disruption of blood and lymphatic vessels should be kept to a minimum [80-82].

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In the field of dermatology, several reports have stated the advantage of the CO2 laser for the surgical removal of non-melanoma skin cancers (such as basal- and squamous cell carcinoma) with maximal preservation of the healthy surrounding area, better tumor regression and good cosmetic outcome [83-88]. In addition, the use of CO2 laser has also been shown to be efficient for the treatment of superficial scars, i.e. acne as well as keloids [89-91]. Finally, other current uses are more centered on dermatologic treatments such as the removal of verrucae [92-94], tattoos (by matching the wavelength of the CO2 laser to the color of the ink), abnormal skin pigmentation [95-97] and facial rejuvenation. For facial rejuvenation, the thermal effect of the laser in the dermis was shown to induce collagenesis which serves the antiaging purpose [98100].

Table 1. Overview of different current uses of the CO2 medical laser. Current use Neurosurgery Operations where blood loss is significant Extirpation of highly vascular tumors Surgery for malignant diseases Basal cell carcinoma Squamous cell carcinoma Scars Verrucae Abnormal pigmentation Facial rejuvenation

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Medical specialty Surgery

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Dermatology

References [71-73] [74-76] [77-79] [80-82] [83-85] [86-88] [89-91] [92-94] [95-97] [98-100]

3.2. Current use of photothermolysis for surgical intervention in addition to drugs treatment or to assist drug delivery As shown in Tables 2-4, the capacity of the CO2 laser to create small channels through the skin has been used as a way to facilitate the transport of drugs across the skin. The outcomes of some studies are described as an increment in the amount of drug retained in the skin. In other cases,

the main findings are related to the increment in the transdermal flux. For this latter group, the steady state transdermal flux is usually estimated from the slope of the linear region (steadystate portion) of the accumulated amounts of the drug against time [101]. The use of fractional ablated laser poration has been more frequently reported than full beam in both the preclinical and clinical studies. Interestingly, fractional laser ablation results in micropores with a diameter generally smaller than 200 µm, which ultimately determines the formulation used in the studies. Surface tension as well as viscosity of the formulation are crucial as they may affect the proper filling of the laser channels and, therefore, the laser-assisted drug delivery [102, 103]. Accordingly, in most of the studies described, drugs were administered in the form of an aqueous solution as first choice for vehicle.

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Fig. 5 illustrates the size of the active molecules that have been investigated in preclinical research and in clinical trials grouped according to the endpoint of the experiment: laser intervention plus drug or drug-delivery based treatments. Clearly, a significant amount of preclinical studies (46%) have made use of macromolecules (molecular weight ≥1000 Da), whereas the majority of the clinical studies (73%) have focused on small molecules (molecular weight <1000 Da). At the same time, in preclinical studies (in vitro and in vivo on animals), the endpoint has usually been the quantification of the increased drug delivery (63%), caused by the ablation of the SC previous to the application of the drug formulations. However, in clinical trials, the endpoint has generally been the clinical outcome (73%), mostly influenced by the laser intervention and only marginally affected by the drug application, which was simply considered additional treatment.

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As can be expected, the energy of laser used in the two different applications, laser surgery vs. laser-assisted drug delivery, has been different. In the case of laser-assisted drug delivery, the energy has been low (≤ 4 mJ), and the result has been the generation of superficial pores (~30 µm). However, in the clinical trials, were the laser treatment was used in primis for surgical purpose (e.g., removal of verrucae) a much higher energy was needed (above 20 mJ). Overall, the conclusion from the results illustrated in Fig. 5 is that the clinical use of the CO2 laser has been mainly oriented to surgery, whereas the tendency of preclinical research has been on the use of the CO2 laser for assisting the delivery of macromolecules.

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Figure 5. Classification of the molecules used with CO 2 surgical lasers according to the endpoint of the experiment (laser intervention with a drug of interest vs laser-assisted drug delivery) and type of experiment performed (preclinical research vs clinical studies). Dashed horizontal line corresponds to a molecular weight value of 1000 Da (threshold between small molecules and macromolecules).

f

Drug

MW (~Da)

Application

Formulation

HYD

110

Dyspigmentation

Buffered solution (pH 7)

130

TXA

157

Basal cell carcinoma Abnormal pigmentation

Findings

Buffered solution (pH 5) Buffered solution (pH 7.4)

Buffered solution (pH 5) Buffered solution (40% PG/PEG 400; pH 5) Buffered solution (50% glycerin; pH 3.5) Hydroalcoholic suspension (40% of either PG/PEG 400/EtOH) Hydroalcoholic solution (40% of either PG/PEG 400/EtOH) Lipid nanoparticles

Tumorous lesions

AA

176

Hydrophilic MM

IMQ

240

Verrucae

CIS

300

Tumorous lesions

Solution (commercially available IV solution)

AA2G

338

Hydrophilic MM

Buffered solution (pH 7.4)

siRNA

Macromolecule model

Macromolecule model

Pr

Aqueous solution

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FD

Hydrophobic MM

Solution (0.9% saline)

Aqueous solution

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PEGs

389 400 1000 2050 3350 4000 10000 20000 40000 10632

e-

168

[104]

R

[105]

47-fold maximum transdermal flux increase vs control P

[106]

38-fold maximum transdermal flux increase vs control

ALA

FITC

Ref.

4.7-fold maximum transdermal flux increase vs control R

pr

5-FU

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Table 2. Summary of drugs used in preclinical research in vitro (rodent, porcine or human skin) with CO2 surgical lasers to enhance cutaneous drug delivery.

R

41-fold maximum transdermal flux increase vs control 5.1-fold maximum transdermal flux increase vs control 65-fold maximum transdermal flux increase vs control R 8.8-fold maximum transdermal flux increase vs control R 5.8-fold maximum transdermal flux increase vs control R 1.4-fold maximum transdermal flux increase vs control R 447-fold maximum deposited amount increase in deep skin layers vs control P 136-fold maximum transdermal flux increase vs control P 13-fold maximum transdermal flux increase vs control

R

Enables permeation in all cases H 86-fold maximum transdermal flux increase vs control R 78-fold maximum transdermal flux increase vs control Enables permeation (0.72 µg/cm2/h) Enables permeation (0.43 µg/cm2/h) 15-fold maximum transdermal flux increase vs control R

[107] [108] [107] [109] [110] [104] [111]

[104]

Tumorous lesions Aqueous solution [112] Macromolecule QDs 18 nm Buffered suspension of nanocrystals (pH 7.4) Fluorescence signal increase in the stratum corneum vs control R [104] model The grey fields indicate adjunct treatments to one of the current uses of the CO2 surgical laser. R Experiments where rodent skin was selected as the in vitro preclinical model. P Experiments where porcine skin was selected as the in vitro preclinical model. H Experiments where human skin was selected as the in vitro preclinical model. 5-FU: 5-fluorouracil; AA: ascorbic acid; AA2G: ascorbic acid 2-glucoside; ALA: 5-aminolevulinic acid; CIS: cisplatin; FD: FITC-labeled dextran; FITC: fluorescein isothiocyanate; HYD: Hydroquinone; IMQ: Imiquimod; MM: molecule model; PEGs: polyethylene glycols; QDs: nanocrystal quantum dots; siRNA: small interfering RNA; TXA: Tranexamic acid.

f

145

Application

Formulation

Tumorous lesions

Cream (Metvix®)

ALA

168

Tumorous lesions

Cream

MB

320

Hydrophilic MM

Coated patches

FITC

389

Hydrophobic MM

Aqueous solution

SRB

560

Hydrophilic MM

Coated patches

siRNA

10632

Tumorous lesions

Aqueous solution

20000

Macromolecule model

Aqueous solution

45000

Protein model

Coated patches

1000000

Tumorous lesions

Aqueous solution

Ref.

8.2-fold fluorescence signal increase vs

control P

[113]

2.8-fold fluorescence signal increase vs

control P

[114]

15-fold maximum deposited amount increase vs control R

[115]

Fluorescence signal increase in deep layers (25 to 75 µm) vs control

Pr

FD TROVA pDNA

Findings

pr

MAL

MW (~Da)

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Drug

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Table 3. Summary of drugs used in preclinical research in vivo (rodent or porcine) with CO2 surgical lasers to enhance cutaneous drug delivery.

63-fold Maximum deposited amount increase vs control

R

[104] [115]

Fluorescence signal increase up to 200 µm deep vs control R

[112]

Fluorescence signal increase in deeper layers (0 to 75 µm) vs control 15-fold maximum deposited amount increase vs control R

R

[104] [115]

Fluorescence signal increase in the epidermis vs control R R

R

[112] P

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The grey fields indicate adjunct treatments to one of the current uses of the CO2 surgical laser. Experiments where rodent was selected as the in vivo preclinical model. Experiments where porcine was selected as the in vivo preclinical model. ALA: 5-aminolevulinic acid; FD: FITC-labeled dextran; FITC: fluorescein isothiocyanate; MAL: methyl aminolevulinate; MB: methylene blue; MM: molecule model; pDNA: plasmid DNA; siRNA: small interfering RNA; SRB: sulforhodamine B; TR-OVA: Texas Red-ovalbumin.

f

MW (~Da)

Application

Formulation

Findings

Ref.

5-FU

130

Basal cell carcinoma

---

[116]

MAL

145

Tumorous lesions

Cream (Metvix®)

ALA

168

Tumorous lesions

Suspension cream

87% histologic clearance after a single application of 5-FLU for 1 week. No control. Higher clinical cure rates at 3 months with lower recurrences at 6. 9 and 12 months but similar tumor clearance than the control. Visual evidence of incorporation of ALA inside the microcolumns

LID

270

Anesthesia

Cream

Enables systemic delivery but with lower concentrations than with full beam Er:YAG laser

[119]

TRE

300

Scars

320

Anesthesia

TA

434

Scars

Complete healing of the nodulocystic acne lesions. Assists topical anesthesia but its aplication is experienced as more painful than with Er:YAG laser Overall improvement of 2.73 on a 0-3 scale

[120]

AH

Gel Solution (with epinefrine; Ultracain D-S forte) Aqueous suspension

CLO

Abnormal pigmentation

Cream

Overall mean improvement score of the study increased from 0.5 (without laser) to 1.35.

[123]

Abnormal pigmentation

Solution (Schering AG)

Higher re-pigmentation scores and patient satisfaction rates.

[124]

SSG

467 500 516 911

Cutaneous leishmaniasis

---

90% of the patients responded well to treatment with good to excellent final cosmesis.

[125]

HGF

>5000

Alopecia

Solution (AQ Skin Solutions®)

PRP

>35000

Scars

PLLA

<140000

Scars

BonNT A

150000

Facial rejuvenation

e-

[117] [118]

[121] [122]

Increases mean hair density

[126]

Solution (Plasma)

No significant differences between topical and intradermal administration

[127]

Microspheres (Sculptra) in saline

95% of the scars improved

[128]

Solution (0.9% saline)

Effectively reduces the severity of wrinkles

[129]

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BETe

pr

Drug

Pr

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Table 4. Summary of drugs used in clinical studies with CO2 surgical lasers to enhance cutaneous drug delivery.

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The grey fields indicate adjunct treatments to one of the current uses of the CO2 surgical laser. 5-FU: 5-fluorouracil; AH: articaine hydrochloride; ALA: 5-aminolevulinic acid; BETe: Betamethasone esters; BonNT A: Botulinum neurotoxin Type A; CLO: clobetasol propionate; HGF: hair growth factor; LID: Lidocaine; MAL: methyl aminolevulinate; PLLA: Poly-L-lactic Acid; PRP: Platelet-rich Plasma; SSG: sodium stibogluconate; TA: triamcinolone acetonide; TRE: Tretinoin.

4. Direct ablation assisted drug delivery: the emergence of the Er:YAG laser Direct ablation was described in 1982 as “the interaction of the laser pulses with the skin that leads to the breakup of the latter and the expulsion of its fragments at supersonic velocities” [130]. However, it was not until 1987 when this approach was used as a mean to increase transdermal drug delivery thanks to the controlled removal of the SC [131].

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The same way that the CO2 laser was the foremost exponent of the photothermic ablation, the Er:YAG laser is the foremost exponent of the direct ablation. Due to its lasing material (erbiumdoped yttrium aluminum garnet; Er:YAG), this laser emits at a wavelength of 2936 nm that targets the tissue water [132]. Compared with the CO2 laser, the wavelength of the Er:YAG laser is absorbed 12-18 times more efficiently (Fig. 3). This difference is of importance because a direct translation of light energy (laser) to mechanical energy (photomechanical but not thermomechanical) results in microexplosions of the water molecules in the skin (creating micropores), thus protecting the surrounding tissue (Fig. 4B) [133].

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As only a small fraction of energy results in thermal damage, the application of the direct ablative lasers is not able to produce cauterization [134]. This is a clear disadvantage when compared with the CO2 in case of surgical interventions. However, when fractionally applied on superficial perforations, Er:YAG laser is less aggressive and presents shorter recovery times due to faster re-epithelization process [135]. This is why this laser has gained its interest for the cutaneous delivery of drug molecules.

4.1. Current use of direct ablation in medical practice (absence of drug).

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As shown Table 5, the Er:YAG laser is commonly used for ocular interventions, more specifically, cataract surgery, where the microincisions facilitate early visual rehabilitation [136-138]. Similarly, the small incisions originated by this type of laser and the subsequent reduced postoperative pain make it a reliable treatment option for the surgery of tumorous lesions [139141].

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Another important field of application for the Er:YAG laser is in dermatology. For instance, some authors have highlighted the benefits of using the Er:YAG laser for the removal of either agerelated pigmentations or tattoos [142-144]. Similarly, small superficial hemangiomas (vascular birthmarks) benign skin growth [145-147] and acne scars [148-150] have been successfully removed following direct ablative procedure as it causes no scarring nor pigmentary changes. Other frequent used applications are the treatment of common warts (verrucae) and wrinkles correction. For the former, is of importance not only because of providing positive outcomes [151-153], but also because the improved safety, since the human papillomavirus DNA does not survive after the ablation [154]. In case of the latter, Er:YAG laser provides a considerable clinical improvement on skin wrinkles with fewer (if any) side-effects when compared with other lasers [155-157].

Table 5. Overview of different current uses of the Er:YAG medical laser. Medical specialty

Current use

References

Surgery

Ocular Tumorous lesions Abnormal pigmentation Vascular birthmarks Benign skin growth Scars Verrucae Wrinkles correction

[136-138] [139-141] [142-144] [145-147] [148-150] [158-160] [151-153] [155-157]

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Dermatology

4.2. Use of direct ablation to facilitate the delivery of drugs across the skin

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The Er:YAG laser has been applied as a drug delivery enhancement technique as an alternative to the CO2 laser [47, 121]. Given the lower skin aggresion, Er:YAG lasers was used for lower epidermis-dermis treatments, whereas those reported for the CO2 laser have been limited to upper epidermis treatments [135, 161]. A summary of the active drug molecules which were investigated in combination with Er:YAG surgical laser for cutaneous drug delivery is given in Tables 6-8.

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For certain molecules such as prednisone or diclofenac sodium, a positive correlation between drug flux and pore depth has been reported [162, 163], whereas for other drugs such as lidocaine, cytochrome C or methotrexate drug flux resulted to be similar despite an increase in the treatment depth [164, 165]. To explain these results, the possible interaction of certain drug molecules with the skin tissue has been hypothesized. In the case of the above-mentioned drugs, their physicochemical properties in terms of molecular weight, lipophilicity (expressed as LogPOCT) or net charge do not give any explanation for their unexpected behavior; however this differentiated behavior could be explained on the basis of their “hydrophilic-lipophilic balance” [166]. Thus, for hydrophilic molecules like lidocaine, methotrexate and cytochrome C (with a calculated HLB of 11.1, 12.4 and 26.4, respectively), an increase of pore depth does not improve the delivery which is already at its maximum. However, for other more lipophilic molecules such as prednisone and diclofenac sodium (with a calculated HLB of 4.56 and 5.81; respectively), the viable epidermis and dermis do represent significant diffusional barriers, and therefore the depth of the pore and the herewith increased area of contact will have a positive effect on the drug delivery flux. With regard to the drug formulations used in preclinical research with Er:YAG surgical lasers, aqueous-based drug formulations have been usually reported. As explained for the CO2 laser, the formulation must be able to penetrate into the micropores and fill them to result in a successful treatment [102, 103]. However, in clinical trials, the use of commercially available creams rather than novel formulations is noteworthy [167]. In addition, it would be interesting to highlight the use of microparticles as drug formulation. While small molecules, macromolecules and biomolecules are able to diffuse across the walls of the micropores into the skin, studies making use of microparticles as delivery systems have found that the particle deposition into the micropores may act as intraepidermal drug depots [168-172].

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The influence of the molecular weight of the drug in its skin permeation has also been evaluated. Preclinical research has demonstrated that laser-assisted delivery enables the local transport of drugs to specific cutaneous targets [162, 170, 173, 174], paying special attention to the delivery of macromolecules (e.g. antibodies [175] or enzymes [176]) into or through the skin [177] (Fig. 6 and Tables 6 and 7). Meanwhile, although clinical trials have been so far mainly oriented to the use of small molecules (79%; Fig. 6 and Table 8), this scenario might change with the increasing presence of as new macromolecular biologicals in the market [178] and the arrival of specifically designed delivery carriers [179-181].

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Figure 6. Classification of the molecules used with Er:YAG surgical lasers according to the endpoint of the experiment (laser intervention with a drug of interest vs laser-assisted drug delivery) and type of experiment performed (preclinical vs clinical studies). Dashed horizontal line corresponds to a molecular weight value of 1000 Da (threshold between small molecules and macromolecules).

f

Drug

MW (~Da)

Application

Formulation

5-FU

130

Tumorous lesions

Buffered solution (pH 5)

oo

Table 6. Summary of drugs used in preclinical research in vitro (rodent, porcine or human skin) with Er:YAG surgical lasers to enhance cutaneous drug delivery. Findings

113-fold maximum transdermal flux increase vs control R

168

Tumorous lesions

Lipophilic cream (Psoralon®) Alcoholic formulation (Levulan®)

AA

176

Hydrophilic MM

Buffered solution (50% glycerin; pH 3.5)

Alopecia

Buffered solution (30% PG)

209

Alopecia

Buffered solution (30% PEG400)

Verrucae

LID

270

Anesthesia

PTX

278

Scars

MOR

285

Analgesia

Pr

240

 Hydroalcoholic suspension (40% of either PG/PEG 400/EtOH)  Hydroalcoholic saturated solution (40% of either PG/PEG 400/EtOH)  Lipid nanoparticles  Buffered solution (pH 5.4)  Liposome-based cream (LMX4®) Microparticles

na l

IMQ

e-

206

MXD

DIC

296

Anti-inflammatory

NAL

357

Analgesia

PRE FITC IngMeb TA MAP MTX BUP

358

Anti-inflammatory Hormonal replacement therapy Hydrophobic MM

Jo ur

IND

358 389 431

Benign skin growth

434

Scars

439

Hydrophilic MM

454 468

Tumorous lesions Analgesia

[105]

 13.8-fold maximum deposited amounts increase vs  7.3–fold maximum deposited amounts increase vs control 260-fold maximum transdermal flux increase vs control R

control P

pr

ALA

DPCP

Ref.

[182] [108]

control P

[183]

5.24-fold maximum transdermal flux increase vs control P

[183]

 18-fold maximum transdermal flux increase vs control R  15-fold maximum transdermal flux increase vs control  9.8-fold maximum transdermal flux increase vs control

[107]

3.91-fold maximum transdermal flux increase vs

 15.3-fold maximum transdermal flux increase vs control P  Enables permeation after 5 min 46.4% of the initial dose administered was delivered P control P

Buffered solution (pH 5)

34.9-fold maximum transdermal flux increase vs

 Aqueous solution  Several hydroalcoholic marketed gels Buffered solution (pH 5)

 10-fold maximum transdermal flux increase vs control P  119-fold maximum transdermal flux increase vs control 32.3-fold maximum transdermal flux increase vs control P

[164] [172] [184] [163] [184]

Buffered solution (50% ethanol; pH 7.4)

30.29-fold maximum transdermal flux increase vs control

R

[185]

Hydroalcoholic solution

Enables permeation in all conditions evaluated vs control P

[162]

Buffered solution (pH 7.4)

165-fold maximum transdermal flux increase vs control R

[174]

Hydroalcoholic gel (Picato®)  Aqueous suspension  Microparticles with TA suspended in water (85 µm) Buffered solution (50% glycerin; pH 3.5) Buffered solution (pH 7.4) Aqueous solution (pH 5)

control P

[186]

Enables permeation in all conditions evaluated vs control P

[170]

Enables deposition in all conditions evaluated vs control R

[108]

Enables permeation in all conditions evaluated vs

173-fold maximum transdermal flux increase vs

control P

[165]

control P

[184]

14.8-fold maximum transdermal flux increase vs

f

22.2% of the initial dose administered was delivered P

Microparticles Buffered solution (pH 7)

Macromolecule model

Buffered solution (pH 7.4)

Macromolecule model

Buffered solution (pH 6.5)

Tumorous lesions

Buffered solution (pH 7)

Tumorous lesions

Buffered solution

Cyt C

12000

Macromolecule model

Aqueous solution

PEP

FD ASOs

hGH

Macromolecule model

Aqueous solution

13.5-fold maximum transdermal flux increase vs control 17-fold maximum transdermal flux increase vs control R 32-fold maximum transdermal flux increase vs control 23-fold maximum transdermal flux increase vs control 12-fold maximum transdermal flux increase vs control 100-fold maximum transdermal flux increase vs control

[172] R

[176]

Enables permeation in all conditions evaluated vs control P 29.9-fold maximum transdermal flux increase vs control R 29.2-fold maximum transdermal flux increase vs control 11.2-fold maximum transdermal flux increase vs control R Up to 19.7% of the initial dose administered was delivered P Enables permeation vs

[187]

control P

[173] [187] [112] [188] [188]

delivered P

[188]

Aqueous solution

Up to 3.1% of the initial dose administered was

Macromolecule model

Buffered solution (pH 7.4)

Enables permeation in all conditions evaluated vs control R

[174]

Macromolecule model

Aqueous solution

Up to 11.8% of the initial dose administered was delivered P

[188]

RD70

70000

Macromolecule model

Polymer film

Up to 2.3% of the initial dose administered was delivered P

[168]

FD

BAS T-IgG OS2966

144000 150000

na l

Macromolecule model

FITC- BSA

38000 40000 70000 150000 70000

Antibody model

Biomacromolecule model

Jo ur

FSH

22000

e-

Hydrophilic MM

siRNA

559 716 1429 2190 2354 2863 4000 10000 20000 5036 8103 10632

oo

Scars

Pr

SRB

531

pr

Vit E

150000

Psoriasis

Buffered solution (pH 7.4) Buffered solution Buffered solution

Increasing laser fluence resulted in antibody delivery

increments P

11.1-fold maximum transdermal flux increase vs control Total delivery increase vs

control P

R

[175] [189] [190]

155000 Autoimmune diseases Buffered solution (pH 7.4) 145-fold maximum total delivery increase vs control P [175] 0.5 µm PSP Macromolecule model Polymer film with microparticles Only the smaller nanoparticles diffuse into the micropore P [168] 5 µm The grey fields indicate adjunct treatments to one of the current uses of the Er:YAG surgical laser. R Experiments where rodent skin was selected as the in vitro preclinical model. P Experiments where porcine skin was selected as the in vitro preclinical model. H Experiments where human skin was selected as the in vitro preclinical model. 5-FU: 5-fluorouracil; AA: ascorbic acid; ALA: 5aminolevulinic acid; ASOs: Antisense oligonucleotides; ATG: antithymocyte gamma globulin polyclonal antibody; BAS: Basiliximab; BUP: Buprenorphine; Cyt C: Cytochrome C; DIC: Diclofenac sodium; DPCP: Diphencyprone; FD: FITC-labeled dextran; FITC: fluorescein isothiocyanate; FITC-BSA: Fluorescein isothiocyanate labelled bovine serum albumin; FSH: follicle-stimulating hormone; hGH: human growth hormone; IMQ: Imiquimod; IND: Indomethacine; IngMeb: Ingenol mebutate; LID: Lidocaine hydrochloride; MAP: Magnesium ascorbyl phosphate; MM: molecule model; MOR: Morphine; MTX: Methotrexate; MXD: Minoxidil; NAL: Nalbuphine; OS2966: monoclonal IgG1 therapeutic antibody; pAcGFP: DNA vector pAcGFP1-C1; PEP: Peptides; PRE: Prednisone; PSP: ATG

f

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Red-fluorescent polystyrene-particles; PTX: pentoxifylline; RD70: rhodamine B-labeled dextrane 70 kDa; siRNA: small interfering RNA; SRB: sulforhodamine B; TA: Triamcinolone acetonide; TIgG: TRITC-conjugated Goat Anti-Mouse IgG; Vit E: D-α-tocopherol succinate.

MW (~Da)

Application

Formulation

Ref.

ALA

168

Tumorous lesions

Buffered solution (pH 5) Buffered solution (40% PG; pH 5)

Deposited amounts increase up to 70 μm depth vs control R

[107]

SRB

559

Hydrophilic MM

Buffered solution (pH 7)

Deposited amounts increase in the SC and epidermis vs control R

[187]

PEP

716 1429 2190

Macromolecule model

Buffered solution (pH 7.4)

Deposited amounts increase up to 160 μm depth vs control R

[176]

ASOs

5036

Tumorous lesions

Buffered solution (pH 7)

Deposited amounts increase in the epidermis vs control R

[187]

siRNA

10632

Tumorous lesions

Aqueous solution

Deposited amounts increase up to 200 μm depth vs control R

[112]

LYS

14300

Vaccine model

Buffered solution

Enables permeation in all conditions evaluated vs control R

[176]

pAcGFP

26900

Tumorous lesions

Buffered solution (pH 7)

164-fold deposited amounts increase vs control R

[187]

HBsAg

27000

Vaccine model

Buffered solution

Pore depth-dependent immunogenicity enhancement R

[191]

ATG pDNA CNTS

na l

Pr

Drug

e-

Findings

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Table 7. Summary of drugs used in preclinical research in vivo (rodent or porcine) with Er:YAG surgical lasers to enhance cutaneous drug delivery.

155000

Autoimmune diseases

Buffered solution (pH 7.4)

41.2-fold maximum transdermal flux increase vs control R

[175]

1000000

Tumorous lesions

Buffered solution

Deposited amounts increase in the epidermis vs control R

[112]

4.0 ± 0.8 µm

Nanoparticle model

Aqueous suspension of microcontainers

Deposited amounts increase up to 200 μm depth vs control R

[169]

The grey fields indicate adjunct treatments to one of the current uses of the Er:YAG surgical laser. R Experiments where rodent was selected as the in vivo preclinical model. P Experiments where porcine was selected as the in vivo preclinical model. ALA: 5-aminolevulinic acid; ASOs: Antisense oligonucleotides; ATG: antithymocyte gamma globulin polyclonal antibody; CNTS: CaCO3 containers filled up by Fe3O4 nanoparticles (14 ± 5 nm); HBsAg: Hepatitis B surface antigen; LYS: Lysozyme; MM: molecule model; pAcGFP: DNA vector pAcGFP1-C1; pDNA: plasmid DNA; PEP: Peptides; siRNA: small interfering RNA; SRB: sulforhodamine B.

f

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Table 8. Summary of drugs used in clinical studies with Er:YAG surgical lasers to enhance cutaneous drug delivery. MW (~Da)

Application

Formulation

Findings

5-FU

130

Tumorous lesions

Cream

Laser-assisted topical 5-FU, in combination with CLO, improved the major outcomes

[192]

MAL

145

Tumorous lesions

Cream (Metvix®)

5.6-fold deposited amounts increase vs control

[193]

IMQ

240

Verrucae

Cream

72.7% of patients achieved complete wart clearance

[194]

LID

270

Anesthesia

Cream

Enables higher systemic delivery than with fractional CO2 laser

[119]

AH

320

Anesthesia

Solution (with epinefrine; Ultracain D-S forte)

Assists topical anesthesia and its aplication is experienced as less painful than with CO2 laser

[121]

CAL

413

Psoriasis

Ointment

Laser-assisted topical CAL improved the results for the drug alone on plaque psoriasis

[195]

PPT

414

Benign skin growth

Solution (Wartec®)

Better efficacy and fewer relapses than laser alone

[196]

CLO

467

Abnormal pigmentation

Cream

Laser-assisted topical CLO, in combination with 5-FU, improved the major outcomes

[192] [197]

Ref.

478

Antibiotic

Cream (Refobacin®)

BET

500

Abnormal pigmentation

Solution (Schering AG)

Marked to excellent improvement on vitiligo plaques

[198]

RAP

914

Abnormal pigmentation

Solution (Rapamune®)

Laser-assisted topical RAP did not improve port wine stains blanching

[199]

rb-bFGF

18500

Abnormal pigmentation

Spray

Majority of the patients were rated with an excellent improvement

[200]

TiO2

<100 nm

Nanoparticle model

Buffered suspension (PEG-300; pH 6)

Enables particle penetration and depot release for a prolonged period of time

[171]

Al2O3

27 µm

na l

GEN

Despite 100-fold delivery increase vs control, no therapeutically active concentrations were achieved

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Pr

e-

pr

Drug

The grey fields indicate adjunct treatments to one of the current uses of the Er:YAG surgical laser. 5-FU: 5-fluorouracil; AH: articaine hydrochloride; Al2O3: alumina; BET: Betamethasone; CAL: calcipotriol; CLO: clobetasol propionate; GEN: Gentamicin; IMQ: Imiquimod; LID: Lidocaine hydrochloride; MAL: methyl aminolevulinate; PPT: podophyllotoxin; RAP: Rapamycin; rb-bFGF: recombinant bovine basic fibroblast growth factor; TiO2: titanium dioxide.

5. Mechanical waves for cutaneous delivery: a revisited old approach An alternative non-invasive mechanism by which laser radiations may enhance cutaneous drug delivery consist on the formation of mechanical waves. Described by Carome and col. in 1964 [201], the mechanical waves (or pressure waves) are generated as a result of the irradiation of a material with a beam of light. When in contact with the skin, the pressure waves originate transient pores within the SC lipids without inflicting ablation [202]. There are two primary laser mechanisms by which mechanical waves for cutaneous delivery are generated: (1) direct irradiation of a material or (2) confined irradiation of a material (Fig. 4C).

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Direct irradiation of a material: The first mechanism for pulsed waves generation involves the irradiation of a material which is in contact with the skin, eventually causing a mechanical impulse. When the skin and the material are in contact, those pressure waves are transmitted to the skin, expanding the lacunar spaces within the intercellular regions of the SC [203, 204]. Essentially, the irradiated material acts as a light-to-pressure energy converter. Some examples of the foils studied are the work by Yang on thin metallic films (such as AI, Ag, Pt, Au or Pb) in 1974 [205], by Fukumura and col. on polystyrene sensitized with anthracene in 1993 [206], by Biagi and col. on chromium in 1997 [207] and on a mixture of epoxy resin and graphite powder in 2001 [208], by Guo and col. on a photonic crystal-metallic structure (a combination of, silicon dioxide, titanium and gold) in 2011 [209], by Sa and col. on piezophotonic materials (based on titanium dioxide and polystyrene) in 2013, or by Xionget and col. either on fluorinated ethylene propylene plastic film with an alluminium coating or on a bilayer film of gold and polyvinyl chloride in 2015 [210].

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Confined irradiation of a material: Confined irradiation follows the same principle than direct irradiation but with an overlay on top of the irradiated material. As a result, the photomechanical waves generated present a higher peak pressure and longer duration [211].

5.1. Current use of mechanical waves in medical practice (without drug molecules)

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Pulsed waves generated by direct or confined irradiation of a material are not currently in use neither in surgery nor for a dermatological application. Moreover, it is worth mentioning that mechanical waves generated through other mechanisms (i.e. Q-switched ruby laser [212, 213]) are nowadays being used for the treatment of abnormal pigmentation of the skin (tattoo removal, birthmarks or solar lentigines) [214-216] or for hair removal [217-219]. However, they are not useful in enhancing cutaneous drug delivery and will not be covered by this review.

5.2. Use of mechanical waves to facilitate the delivery of drugs across the skin Several authors have made use of mechanical waves to enhance the transcutaneous delivery of drugs, without destroying the skin barrier. However, as shown in Table 9, this strategy has received significantly less attention than classical ablative laser poration. To our knowledge, only 16 drug molecules have been investigated with this approach, compared to the ~40 and ~70 investigated for CO2 and Er:YAG laser ablation, respectively. One possible explanation for the limited focus on the use of mechanical waves might be found in the studies performed by Lee et al. [176, 184, 220]. In these studies, the drug delivery enhancement of the mechanical waves was compared to Er:YAG ablative poration for 6 molecules (285, 389, 716, 1429, 2190 and 9266

Da). The results showed that, under the effect of the pressure waves, only 3 molecules were efficiently delivered, whereas upon direct ablation with Er:YAG, the delivery of all tested molecules was enhanced. While these results might have discouraged the use of mechanical waves, it is to be noticed that these studies were performed with a laser potency typically used for superficial ablation of the skin and not optimized for the generation of mechanical waves. In this sense, it is expected that the type of irradiated material as well as the wavelength and energy of the laser will significantly influence the nature of the mechanical waves [34, 221]. An advantage of the pressure waves relies on the fact that they can controllably and reversibly reduce the skin barrier and elicit temporary increases in its permeability without inflicting ablation. As a counterpart, whilst the results obtained with CO2 and Er:YAG lasers demonstrated a targeted delivery into and across the skin, the recovery of the barrier function after the application of the pressure waves occurs in within minutes, which may explain the constrained diffusion of drugs to the epidermis.

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In these circumstances, the characteristics of the drug formulations used for pressure waveassisted delivery are different than in case of laser-microporation. The potential to penetrate into small pores and valleys may not be as important as the effect of the different components of the formulation to increase the skin impairment and hence the success of the technique [222].

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Interestingly, despite of the limited knowledge about this technique, it is remarkable that only 31% of the drug candidates were small molecules (< 1000 Da) (Figure 7). Although macromolecules do not seem the most suitable candidate for pressure waves enhanced delivery, it seems that a evaluation and characterization of the technique is being carried out with them, perhaps as an attempt to facilitate the incorporation of this technology into the pharmaceutical [220, 223] or cosmetic industry [224, 225]. Overall, it could be speculated that the potential of pressure waves for enhancing the penetration of drugs has been underestimated.

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Figure 7. Classification of the molecules used with mechanical waves according to the endpoint of the experiment (laser intervention with a drug of interest vs laser-assisted enhanced drug delivery) and type of experiment performed (preclinical vs clinical studies). Dashed horizontal line corresponds to a molecular weight value of 1000 Da (threshold between small molecules and macromolecules).

In vivo

MW (~Da)

Application

Formulation

DNCB

203

Contact dermatitis

Acetone

MOR

285

Analgesia

FITC

389

Hydrophobic molecule model

PEP

716 1429 2190

Macromolecule model

siRNA

9266

Tumorous lesions

Aqueous solution

rBd

40000

Macromolecule model

Aqueous solution

fLP

20 nm

Nanoparticle model

Aqueous suspension

Clinical

ALA

In vitro

HA

Black polystyrene

Aqueous solution

Er:YAG

Black polystyrene

Aqueous solution

Er:YAG

Black polystyrene

Buffered solution (pH 7.4)

Er:YAG

Black polystyrene

Er:YAG

Black polystyrene

Nanoparticle model

Aqueous suspension in 2% sodium lauryl sulfate

168

Tumorous lesions

Solution

15000

Wrinkles correction

Aqueous gel

Wrinkles correction

Buffered gel (pH 7.4)

800000

Macromolecule model Macromolecule model

BAC

1100

GFP

28000

INS

6000

Diabetes

Aqueous solution

rBd

40000

Macromolecule model

Aqueous solution

In vivo

f

Q-switched ruby

pr

Material

100 nm

Jo ur

Confined irradiation

fMS

Laser used

e-

Direct irradiation

In vitro

Drug

Pr

Type of experiment

na l

Laser mechanisms

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Table 9. Summary of drugs used with mechanical waves to enhance cutaneous drug delivery.

Hydroalcoholic gel Hydroalcoholic gel

Q-switched ruby Q-switched ruby Q-switched ruby Q-switched ruby Q-switched Nd:YAG Q-switched Nd:YAG Q-switched Nd:YAG Q-switched Nd:YAG Q-switched ruby Q-switched ruby

Findings

Black polystyrene Black polystyrene Black polystyrene Black polystyrene Piezophotonic Mn-TUP polystyrene

in

Piezophotonic Piezophotonic

Response was observed due to PW delivery and not when passively administered P ~14-fold maximum transdermal flux increase with vs control P No statistical differences vs control R ~4.82-fold maximum transdermal flux increase with for 2190 MW vs control. No differences for the other 2 R ~5.3-fold maximum transdermal flux increase with vs control R ~1.8-fold deposited amounts increase up to 50 μm depth vs control R ~3.5-fold deposited amounts increase vs control R Delivery was facilitated into the epidermis R ~6.8-fold deposited amounts increase vs control H Deposited amounts in the epidermis increase vs control H Delivery was facilitated up to 50 μm depth P ~5.3-fold maximum deposited amounts increase vs control P Delivery was facilitated up to 50 μm depth P

Ref. [226] [184] [220] [176] [220] [227] [227] [228] [229] [224] [225] [221] [221]

Black polystyrene

Blood glucose decreased 80% R

[223]

Black polystyrene

Delivery was facilitated up to 400 μm depth R

[211]

f

15000

Wrinkles correction

Hydroalcoholic gel

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Pr

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pr

HA

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Q-switched Piezophotonic Improvement in facial rejuvenation H [224] Nd:YAG R Experiments where rodent was selected as the in vitro preclinical model. P Experiments where porcine was selected as the in vitro preclinical model. H Experiments where human skin was selected as the in vitro preclinical model or in clinical studies. ALA: 5-aminolevulinic acid; BAC: Bacteriochlorin; DNCB: Dinitrochlorobenzene; FITC: fluorescein isothiocyanate; fLP: fluorescent latex particles; fMS: fluorescent microspheres; GFP: green fluorescent protein; HA: Hyaluronic acid; INS: Insulin; MOR: Morphine; PEP: Peptides; rBd: rhodamine B dextran; siRNA: small interfering RNA. Clinical

6.

Future perspectives

Since the development of fractional photothermolysis in 2004 [47] and fractional ablative laser in 2010 [48], different active technologies have been developed (i.e. P.L.E.A.S.E. (Precise Lasers EpidermAl SystEm) microporation technology), marketed (i.e. P.L.E.A.S.E.® Professional) and, in some cases, withdrawn from the market later for different reasons (i.e. P.L.E.A.S.E.® Private). The hurdles in this area may arise from the necessity to develop a patient-friendly device compiling with the acceptable cost and the regulatory requirements. In this regard, we must keep in mind that new laser devices are being developed and lasers already in place have been significantly improved in terms of cost, security and effectiveness (i.e. Nd:YAG laser).

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In the sixty years since the first laser was built, the development of dermatological laser technology has evolved significantly to a point where it is now possible to find laser devices that are portable, handheld and easy to use. The type and the safety of the lasers available have also increased significantly, allowing the treatment of a diverse range of skin conditions. Advances in laser pulsing, scanning, and fractionation have revolutionized skin treatments, allowing for better clinical results and quicker patient recovery. However, safety concerns (i.e. potential eye and skin damage), as well as the need to improve the precision, efficiency and transmission of laser going through the multiple layers of skin means that the technology needs subsequent improvements. Irrespective of this, it is worthy to highlight a recent technology named “sonoillumination” that involves the combination of two well-established technologies: ultrasonic pulsation and Q-switched Nd:YAG laser, in order to improve the efficacy, reduce the side effects, and lower the risk of eye damage [230]. Another example is the non-invasive technology developed by LaserLeap Technologies, whereby the combination of nanosecond pulsed laser excitation with piezophotonic materials, resulted in high-frequency ultrasound waves that facilitate the diffusion of drugs or cosmetics through the skin [221, 225]. The generation of such pressure waves is suggested as an alternative skin permeation enhancement approach using simple and compact lasers.

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The global dermatology laser market was valued at USD 1205 million in 2017 and it is expected to reach USD 2075 million by the end of 2025 [231]. Laser ablation of the skin has been the working mechanism on which commercialized skin drug delivery devices have been based (i.e. the device formerly known as Epicure Easytouch from Norwood Abbey and the fractional P.L.E.A.S.E. device from Pantec Biosolutions AG).

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Considering all this, continuing future laser technological developments are expected as noninvasive drug delivery approaches are on demand by patients. Multifunctional devices are foreseeable whereby future applications will combine different directed energy sources to optimize results in different fields ranging from drug and preventive/therapeutic vaccines delivery to dermatology applications including: skin preparation for cutaneous delivery of large molecules, epidermal and intradermal clinical interventions, and laser treatments in cosmetic dermatology. Safety standardization and appropriate regulations to avoid both eye and skin damage will need to go hand-by-hand with market development, followed by clinical evidence of safety and efficacy.

7. Conclusions Laser technology is an effective strategy to bypass the skin major defensive barrier, namely the stratum corneum. Studies to increase the passage of drug molecules through the skin via laser technology (photothermolysis, direct ablation and mechanical waves) were investigated and systematically reviewed.

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The use of classic ablative lasers (either photothermolysis (e.g. CO2 laser) or direct ablation (e.g. Er:YAG laser)) at the preclinical level has shown a potential for advanced drug delivery of classical small molecules as well as novel biologics. The creation of microchannels in the skin, which increase the contact and penetration area of the active ingredients in addition to the elimination of the SC, favored the skin penetration and systemic delivery of molecules with MW above 1000 Da. This is a major breakthrough for modern drug delivery given that most of the innovative therapeutics are macromolecules. However, these results have not yet been translated to humans, since most of the clinical studies published so far used traditional small molecular weight molecules in combination with laser therapy. One possible explanation could be that the major focus of such studies was not enhancing the delivery of the drug candidate, but the laser treatment itself. However, such studies already hint at future possibilities.

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Despite its potential, the major drawback of laser ablation is its invasiveness. Such damage is not inflicted by mechanical waves, as they rely on a controlled and transitory alteration of the skin barrier which allows the increase passage of drug molecules in a limited timeframe. This technique though has been mostly neglected by researchers, given the rather modest outcomes recorded so far. However, it is possible that the full potential of this technique has not been revealed yet, and its eventual applicability for high molecular weight novel biomolecules would open a new horizon for laser assisted cutaneous drug delivery.

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Regardless of the type of the laser, laser-assisted drug delivery offers a series of advantages in comparison with passive cutaneous delivery and with parenteral products (i.e. easy of accessibility, non-invasive, increase drug delivery flux through the skin). However, such devices have not been developed commercially yet. Medical lasers developments have been based on the knowledge acquired by interdisciplinary teams composed of physicians, clinicians, dermatologists and researchers both in industry and academia. And thanks to these collaborations, progress has been made on the finding of ever-growing applications in the biomedical field. More research needs to be done in terms of efficacy, safety, dosing, timing, laser platform, and effects of laser settings on the delivery of drugs. Therefore, laser-assisted and ablative fractional laser-assisted drug delivery may become important part dermatology. In summary, although laser-based drug delivery technology is not fully developed and presents potential difficulties that must be overcome, it looks very promising and is likely to revolutionize cutaneous drug delivery in the near future.

8. Acknowledgements We would like to acknowledge the University of Santiago de Compostela, the Xunta de Galicia, and the Fondo Europeo de Desenvolvemento Rexional for financial support. SR acknowledges Dr. Verena Santer for providing valuable comments.

9. Funding

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This work has received financial support from the Consellería de Cultura, Educación e Ordenación Universitaria (Competitive Reference Groups (Ref: ED431C 2017/09) and Centro singular de investigación de Galicia (accreditation 2016‐2019; Ref: ED431G/05)) and the European Regional Development Fund (ERDF).

10. References

-p

[1] V. Dubey, D. Mishra, M. Nahar, and N.K. Jain, Vesicles as tools for the modulation of skin

permeability, Expert Opin Drug Deliv. 4 (2007) 579-93 DOI: 10.1517/17425247.4.6.579. [2] Z. Nemes and P.M. Steinert, Bricks and mortar of the epidermal barrier, Exp Mol Med. 31

(1999) 5-19 DOI: 10.1038/emm.1999.2.

re

[3] Y.N. Kalia, I. Alberti, N. Sekkat, C. Curdy, A. Naik, and R.H. Guy, Normalization of stratum

Jo

ur

na

lP

corneum barrier function and transepidermal water loss in vivo, Pharm. Res. 17 (2000) 1148-50. [4] G. Odland, Structure of the skin. Vol. . 1991: In: Goldsmith, L.A. (editor) Physiology, biochemistry, and molecular biology of the skin. Oxford University Press, Oxford. . [5] U. Jacobi, H.J. Weigmann, J. Ulrich, W. Sterry, and J. Lademann, Estimation of the relative stratum corneum amount removed by tape stripping, Skin Res. Technol. 11 (2005) 91-6 DOI: 10.1111/j.1600-0846.2005.00094.x. [6] C.A. Lipinski, F. Lombardo, B.W. Dominy, and P.J. Feeney, Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings, Adv Drug Deliv Rev. 46 (2001) 3-26. [7] Y.B. Choy and M.R. Prausnitz, The Rule of Five for Non-Oral Routes of Drug Delivery: Ophthalmic, Inhalation and Transdermal, Pharmaceutical research. 28 (2011) 943-948 DOI: 10.1007/s11095-010-0292-6. [8] M. Morishita and K. Park, Biodrug Delivery Systems: Fundamentals, Applications and Clinical Development. 2016: CRC Press. [9] J.D. Bos and M.M. Meinardi, The 500 Dalton rule for the skin penetration of chemical compounds and drugs, Exp. Dermatol. 9 (2000) 165-169. [10] J. Wepierre, L’impermeabilité de la peau la sours à l’égard du perhydrosqualene tritié, Ann. Pharm. Fr. 25: (1967) 515-519. [11] S. Wiedersberg and R.H. Guy, Transdermal drug delivery: 30+ years of war and still fighting!, J Control Release. 190 (2014) 150-6 DOI: 10.1016/j.jconrel.2014.05.022. [12] Research Nester, Transdermal Drug Delivery Market: Global Demand Analysis & Opportunity Outlook 2024. 2018. p. 205.

[13] A.C. Watkinson, M.C. Kearney, H.L. Quinn, A.J. Courtenay, and R.F. Donnelly, Future of the

Jo

ur

na

lP

re

-p

ro of

transdermal drug delivery market--have we barely touched the surface?, Expert Opin Drug Deliv. 13 (2016) 523-32 DOI: 10.1517/17425247.2016.1130034. [14] A.C. Williams and B.W. Barry, Penetration enhancers, Advanced Drug Delivery Reviews. 56 (2004) 603-618 DOI: https://doi.org/10.1016/j.addr.2003.10.025. [15] P.J. Lee, N. Ahmad, R. Langer, S. Mitragotri, and V. Prasad Shastri, Evaluation of chemical enhancers in the transdermal delivery of lidocaine, International Journal of Pharmaceutics. 308 (2006) 33-39 DOI: https://doi.org/10.1016/j.ijpharm.2005.10.027. [16] S. del Río-Sancho, C.E. Serna-Jimenez, M. Sebastian-Morello, M.A. Calatayud-Pascual, C. Balaguer-Fernandez, A. Femenia-Font, Y.N. Kalia, V. Merino, and A. Lopez-Castellano, Transdermal Therapeutic Systems for Memantine Delivery. Comparison of Passive and Iontophoretic Transport, Int. J. Pharm. 517 (2017) 104-111 DOI: 10.1016/j.ijpharm.2016.11.038. [17] M. Ochoa, C. Mousoulis, and B. Ziaie, Polymeric microdevices for transdermal and subcutaneous drug delivery, Advanced Drug Delivery Reviews. 64 (2012) 1603-1616 DOI: https://doi.org/10.1016/j.addr.2012.09.035. [18] Y.N. Kalia, A. Naik, J. Garrison, and R.H. Guy, Iontophoretic drug delivery, Advanced Drug Delivery Reviews. 56 (2004) 619-658 DOI: https://doi.org/10.1016/j.addr.2003.10.026. [19] H. Lee, C. Song, S. Baik, D. Kim, T. Hyeon, and D.-H. Kim, Device-assisted transdermal drug delivery, Advanced Drug Delivery Reviews. 127 (2018) 35-45 DOI: https://doi.org/10.1016/j.addr.2017.08.009. [20] U. Pliquett, Mechanistic studies of molecular transdermal transport due to skin electroporation, Advanced Drug Delivery Reviews. 35 (1999) 41-60 DOI: https://doi.org/10.1016/S0169-409X(98)00062-3. [21] M.R. Prausnitz, A practical assessment of transdermal drug delivery by skin electroporation, Advanced Drug Delivery Reviews. 35 (1999) 61-76 DOI: https://doi.org/10.1016/S0169-409X(98)00063-5. [22] S. Mitragotri, Devices for overcoming biological barriers: The use of physical forces to disrupt the barriers, Advanced Drug Delivery Reviews. 65 (2013) 100-103 DOI: https://doi.org/10.1016/j.addr.2012.07.016. [23] M. Ogura, S. Paliwal, and S. Mitragotri, Low-frequency sonophoresis: Current status and future prospects, Advanced Drug Delivery Reviews. 60 (2008) 1218-1223 DOI: https://doi.org/10.1016/j.addr.2008.03.006. [24] S. Mitragotri and J. Kost, Low-frequency sonophoresis: A review, Advanced Drug Delivery Reviews. 56 (2004) 589-601 DOI: https://doi.org/10.1016/j.addr.2003.10.024. [25] Y.B. Schuetz, A. Naik, R.H. Guy, and Y.N. Kalia, Emerging strategies for the transdermal delivery of peptide and protein drugs, Expert Opin. Drug Deliv. 2 (2005) 533-48 DOI: 10.1517/17425247.2.3.533. [26] M.R. Prausnitz and R. Langer, Transdermal drug delivery, Nat Biotechnol. 26 (2008) 1261-8 DOI: 10.1038/nbt.1504. [27] M.R. Prausnitz, S. Mitragotri, and R. Langer, Current status and future potential of transdermal drug delivery, Nat Rev Drug Discov. 3 (2004) 115-24 DOI: 10.1038/nrd1304. [28] M. Singhal and Y.N. Kalia, Iontophoresis and Electroporation, in Skin Permeation and Disposition of Therapeutic and Cosmeceutical Compounds, K. Sugibayashi, Editor. 2017, Springer Japan: Tokyo. p. 165-182. [29] T. Hikima and K. Tojo, Combined Use of Iontophoresis and Other Physical Methods, in Percutaneous Penetration Enhancers Physical Methods in Penetration Enhancement, N. Dragicevic and H. I. Maibach, Editors. 2017, Springer Berlin Heidelberg: Berlin, Heidelberg. p. 353-367. [30] I. Research, Global aesthetic laser market forecast 2018-2026. 2018.

[31] M.R. Engine, Medical Laser Market By Application (Ophthalmology, Cardiovascular,

Jo

ur

na

lP

re

-p

ro of

Gynaecology, Dermatology, Urology, Dentistry); By Product Type (Diode Laser Systems, Gas laser systems, Solid state laser systems, Dye Laser Systems) and by Regional Analysis - Global Forecast by 2017 - 2024. 2018. p. 110. [32] T.M. Research, Dermatology Lasers Market - Global Industry Analysis, Size, Share, Growth, Trends and Forecast 2018 - 2026. 2018. [33] M.a. Markets, Medical Laser Market by Product (Ho:Yag, Nd:Yag, KTP, Alexandrite, Erbium, Ruby, CO2, Argon, Krypton, He-Ne, Excimer, Dye & Diode), Application (Ophthalmology, Dermatology, Gynecology, Dentistry, Urology, Cardiovascular) Forecast to 2019. 2019. [34] A.G. Doukas and N. Kollias, Transdermal drug delivery with a pressure wave, Adv. Drug Deliv. Rev. 56 (2004) 559-79 DOI: 10.1016/j.addr.2003.10.031. [35] L.R. Sklar, C.T. Burnett, J.S. Waibel, R.L. Moy, and D.M. Ozog, Laser assisted drug delivery: a review of an evolving technology, Lasers Surg Med. 46 (2014) 249-62 DOI: 10.1002/lsm.22227. [36] C.H. Lin, I.A. Aljuffali, and J.Y. Fang, Lasers as an approach for promoting drug delivery via skin, Expert Opin. Drug Deliv. 11 (2014) 599-614 DOI: 10.1517/17425247.2014.885501. [37] L.A. Zaleski-Larsen and S.G. Fabi, Laser-Assisted Drug Delivery, Dermatol Surg. 42 (2016) 919-31 DOI: 10.1097/dss.0000000000000556. [38] M. Haedersdal, A.M. Erlendsson, U. Paasch, and R.R. Anderson, Translational medicine in the field of ablative fractional laser (AFXL)-assisted drug delivery: A critical review from basics to current clinical status, J. Am. Acad. Dermatol. 74 (2016) 981-1004 DOI: 10.1016/j.jaad.2015.12.008. [39] J.S. Waibel, A. Rudnick, D.R. Shagalov, and D.M. Nicolazzo, Update of Ablative Fractionated Lasers to Enhance Cutaneous Topical Drug Delivery, Advances in therapy. 34 (2017) 1840-1849 DOI: 10.1007/s12325-017-0516-9. [40] G. Thomas and R. Isaacs, Basic principles of lasers, Anaesthesia & Intensive Care Medicine. 12 (2011) 574-577 DOI: https://doi.org/10.1016/j.mpaic.2011.09.013. [41] A. Einstein, Zur quantentheorie der strahlung, Phys. Z. 18 (1917) 121-128. [42] K.U. Song, Footprints in Laser Medicine and Surgery: Beginnings, Present, and Future, Medical Lasers; Engineering, Basic Research, and Clinical Application. 6 (2017) 1-4. [43] S. Gianfaldoni, G. Tchernev, U. Wollina, M. Fioranelli, M.G. Roccia, R. Gianfaldoni, and T. Lotti, An Overview of Laser in Dermatology: The Past, the Present and… the Future (?), Open access Macedonian journal of medical sciences. 5 (2017) 526. [44] M.L. Geiges, History of Lasers in Dermatology, Current Problems in Dermatology. 42 (2011) 1-6 DOI: 10.1159/000328225. [45] R.R. Anderson and J.A. Parrish, Selective photothermolysis: precise microsurgery by selective absorption of pulsed radiation, Science. 220 (1983) 524-7. [46] D. Strickland and G. Mourou, Compression of amplified chirped optical pulses, Optics Communications. 56 (1985) 219-221 DOI: https://doi.org/10.1016/00304018(85)90120-8. [47] D. Manstein, G.S. Herron, R.K. Sink, H. Tanner, and R.R. Anderson, Fractional photothermolysis: a new concept for cutaneous remodeling using microscopic patterns of thermal injury, Lasers Surg Med. 34 (2004) 426-38 DOI: 10.1002/lsm.20048. [48] M. Hædersdal, F.H. Sakamoto, W.A. Farinelli, A.G. Doukas, J. Tam, and R.R. Anderson, Fractional CO2 laser‐assisted drug delivery, Lasers in Surgery and Medicine: The Official Journal of the American Society for Laser Medicine and Surgery. 42 (2010) 113122. [49] A. Henderson, Guide to Laser Safety. 1997: Springer US.

[50] W.J. McCarthy, A.U.C.f. Strategy, and Technology, Directed Energy and Fleet Defense:

Jo

ur

na

lP

re

-p

ro of

Implications for Naval Warfare. 2000: Center for Strategy and Technology, Air War College, Air University. [51] W. Koechner and M. Bass, Solid-State Lasers: A Graduate Text. 2003: Springer New York. [52] W. Koechner, Solid-state laser engineering. 1988: Springer-Verlag. [53] Q. Peng, A. Juzeniene, J. Chen, L.O. Svaasand, T. Warloe, K.-E. Giercksky, and J. Moan, Lasers in medicine, Reports on Progress in Physics. 71 (2008) 056701. [54] M. Lukač, T. Sult, and R. Sult, New Options and Treatment Strategies with the VSP Erbium YAG Aesthetics Lasers, J. Laser Health Academy. 2007 (2007). [55] U.A. Patil and L.D. Dhami, Overview of lasers, Indian Journal of Plastic Surgery : Official Publication of the Association of Plastic Surgeons of India. 41 (2008) S101-S113. [56] K. Scholle, P. Fuhrberg, P. Koopmann, and S. Lamrini, 2 Μm Laser Sources and Their Possible Applications. 2010: INTECH Open Access Publisher. [57] R.W. Waynant, Lasers in Medicine. 2001: CRC Press. [58] H. Lubatschowski, Overview of commercially available femtosecond lasers in refractive surgery, Journal of Refractive Surgery. 24 (2008) S102. [59] M.B. Taylor, M. Lukac, M. Gorjan, and K. Nemes, Combined fractional and bulk heating modality for Nd: YAG laser skin treatments, Journal of the Laser and Health Academy. 2012 (2012) 26-34. [60] B. Zgavec and N. Stopajnik, Clinical and histological evaluation of Er: YAG ablative fractional skin resurfacing, J Laser Health Acad. 1 (2014) 1-06. [61] N. Dragicevic and H.I. Maibach, Percutaneous Penetration Enhancers Drug Penetration Into/Through the Skin: Methodology and General Considerations. 2017: Springer Berlin Heidelberg. [62] C.K.N. Patel, Continuous-Wave Laser Action on Vibrational-Rotational Transitions of C O 2, Physical review. 136 (1964) A1187. [63] T. Omi and K. Numano, The Role of the CO(2) Laser and Fractional CO(2) Laser in Dermatology, Laser Therapy. 23 (2014) 49-60 DOI: 10.5978/islsm.14-RE-01. [64] J. Ferguson and J.S. Dover, Photodermatology. 2006: CRC Press. [65] M.P. Goldman, R.E. Fitzpatrick, E.V. Ross, S.L. Kilmer, and R.A. Weiss, Lasers and Energy Devices for the Skin. 2013: Taylor & Francis. [66] K.T. Schomacker, J.T. Walsh, T.J. Flotte, and T.F. Deutsch, Thermal damage produced by high-lrradiance continuous wave CO2 laser cutting of tissue, Lasers in Surgery and Medicine. 10 (1990) 74-84 DOI: 10.1002/lsm.1900100115. [67] E.V. Ross, Y. Domankevitz, M. Skrobal, and R.R. Anderson, Effects of CO2 laser pulse duration in ablation and residual thermal damage: implications for skin resurfacing, Lasers Surg Med. 19 (1996) 123-9 DOI: 10.1002/(SICI)1096-9101(1996)19:2<123::AIDLSM1>3.0.CO;2-U. [68] A.N. Kauvar, H.A. Waldorf, and R.G. Geronemus, A histopathological comparison of "charfree" carbon dioxide lasers, Dermatol Surg. 22 (1996) 343-8. [69] I. Kaplan and S. Giler, CO2 Laser Surgery. 2012: Springer Berlin Heidelberg. [70] S.R. Cohen, A. Goodacre, S. Lim, J. Johnston, C. Henssler, B. Jeffers, A. Saad, and T. Leong, Clinical Outcomes and Complications Associated with Fractional Lasers: A Review of 730 Patients, Aesthetic Plast Surg. 41 (2017) 171-178 DOI: 10.1007/s00266-016-0767x. [71] M. Brock, Modern Neurosurgery 1. 2013: Springer Berlin Heidelberg. [72] E. Belykh, K. Yagmurlu, N.L. Martirosyan, T. Lei, M. Izadyyazdanabadi, K.M. Malik, V.A. Byvaltsev, P. Nakaji, and M.C. Preul, Laser application in neurosurgery, Surg Neurol Int. 8 (2017) 274 DOI: 10.4103/sni.sni_489_16. [73] Robert W. Ryan, Tamir Wolf, Robert F. Spetzler, Stephen W. Coons, Yoel Fink, and Mark C. Preul, Application of a flexible CO2 laser fiber for neurosurgery: laser-tissue

Jo

ur

na

lP

re

-p

ro of

interactions, Journal of Neurosurgery. 112 (2010) 434-443 DOI: 10.3171/2009.7.jns09356. [74] W. Waidelich and R. Waidelich, LASER Optoelectronics in Medicine: Proceedings of the 7th Congress International Society for Laser Surgery and Medicine in Connection with Laser 87 Optoelectronics. 2012: Springer Berlin Heidelberg. [75] C. Marchica, F. Zawawi, and S.J. Daniel, Management of cricopharyngeal achalasia in an 8month child using endoscopic cricopharyngeal myotomy, International Journal of Pediatric Otorhinolaryngology. 101 (2017) 137-140 DOI: https://doi.org/10.1016/j.ijporl.2017.07.037. [76] G.B. Morand, K. Lambercy, P. Guilcher, and K.B. Sandu, Congenital pharyngeal webs: Treatment of a rare clinical entity by endoscopic CO2 laser approach, International Journal of Pediatric Otorhinolaryngology. 102 (2017) 123-126 DOI: https://doi.org/10.1016/j.ijporl.2017.08.001. [77] A. Sepulveda and E.P. Buchanan, Vascular Tumors, Seminars in Plastic Surgery. 28 (2014) 49-57 DOI: 10.1055/s-0034-1376260. [78] J. Nguyen, L.W. Chapman, D.Z. Korta, and C.B. Zachary, Laser treatment of cutaneous angiokeratomas: A systematic review, Dermatol Ther. (2017) DOI: 10.1111/dth.12558. [79] S. Chinnadurai, N.A. Sathe, and T. Surawicz, Laser treatment of infantile hemangioma: A systematic review, Lasers Surg Med. 48 (2016) 221-33 DOI: 10.1002/lsm.22455. [80] K. Luna-Ortiz, S.C. Hidalgo-Bahena, T.L. Muñoz-Gutiérrez, and A. Mosqueda-Taylor, Tumors of the oral cavity: CO2 laser management, Medicina oral, patologia oral y cirugia bucal. 24 (2019) e84-e88 DOI: 10.4317/medoral.22811. [81] S.W. Lanigan, Lasers in Dermatology. 2012: Springer London. [82] R. Carachi and J.L. Grosfeld, The Surgery of Childhood Tumors. 2016: Springer Berlin Heidelberg. [83] V.D. Mandel, F. Arginelli, G. Pellacani, and M. Greco, Combined carbon dioxide laser with photodynamic therapy for the treatment of nodular and infiltrative basal cell carcinoma, G Ital Dermatol Venereol. 152 (2017) 672-674 DOI: 10.23736/s03920488.16.05395-5. [84] B.P. Hibler, H. Sierra, M. Cordova, W. Phillips, M. Rajadhyaksha, K.S. Nehal, and A.M. Rossi, Carbon dioxide laser ablation of basal cell carcinoma with visual guidance by reflectance confocal microscopy: a proof-of-principle pilot study, Br J Dermatol. 174 (2016) 1359-64 DOI: 10.1111/bjd.14414. [85] F.N. Mirza and K.A. Khatri, The use of lasers in the treatment of skin cancer: A review, J Cosmet Laser Ther. 19 (2017) 451-458 DOI: 10.1080/14764172.2017.1349321. [86] M. Colecchia, N. Nicolai, P. Secchi, G. Bandieramonte, A.M. Paganoni, L.M. Sangalli, G. Pizzocaro, L. Piva, and R. Salvioni, pT1 penile squamous cell carcinoma: a clinicopathologic study of 56 cases treated by CO2 laser therapy, Anal Quant Cytol Histol. 31 (2009) 153-60. [87] D.H. Tang, S. Yan, S.R. Ottenhof, D. Draeger, A.S. Baumgarten, J. Chipollini, C. Protzel, Y. Zhu, D.-w. Ye, O.W. Hakenberg, S. Horenblas, N.A. Watkin, and P.E. Spiess, Laser ablation as monotherapy for penile squamous cell carcinoma: A multi-center cohort analysis, Urologic Oncology: Seminars and Original Investigations. (2017) DOI: https://doi.org/10.1016/j.urolonc.2017.09.028. [88] V.H. Nargund, D. Raghavan, and H.M. Sandler, Urological Oncology. 2015: Springer London. [89] P.B. Tripathi, J.S. Nelson, and B.J. Wong, Posttraumatic Laser Treatment of Soft Tissue Injury, Facial Plast Surg Clin North Am. 25 (2017) 617-628 DOI: 10.1016/j.fsc.2017.06.012. [90] G. Elcin and B. Yalici-Armagan, Fractional carbon dioxide laser for the treatment of facial atrophic acne scars: prospective clinical trial with short and long-term evaluation, Lasers Med Sci. 32 (2017) 2047-2054 DOI: 10.1007/s10103-017-2322-7.

[91] A. Annabathula, C.S. Sekar, and C.R. Srinivas, Fractional Carbon Dioxide, Long Pulse Nd:YAG

Jo

ur

na

lP

re

-p

ro of

and Pulsed Dye Laser in the Management of Keloids, J Cutan Aesthet Surg. 10 (2017) 76-80 DOI: 10.4103/jcas.jcas_136_16. [92] G. Oni and P.J. Mahaffey, Treatment of recalcitrant warts with the carbon dioxide laser using an excision technique, J. Cosmet. Laser Ther. 13 (2011) 231-6 DOI: 10.3109/14764172.2011.606465. [93] P. Campolmi, P. Bonan, G. Cannarozzo, A. Bassi, N. Bruscino, M. Arunachalam, M. Troiano, T. Lotti, and S. Moretti, Highlights of thirty-year experience of CO2 laser use at the Florence (Italy) department of dermatology, TheScientificWorldJournal. 2012 (2012) 546528-546528 DOI: 10.1100/2012/546528. [94] N.H. Boroujeni and F. Handjani, Cryotherapy versus CO(2) laser in the treatment of plantar warts: a randomized controlled trial, Dermatology practical & conceptual. 8 (2018) 168-173 DOI: 10.5826/dpc.0803a03. [95] J.F. Millan-Cayetano, A. Alegre-Sanchez, and P. Boixeda, Treatment of red tattoo reaction using CO2 laser, Lasers Med Sci. (2017) DOI: 10.1007/s10103-017-2229-3. [96] A.A. Meesters, M.A. De Rie, and A. Wolkerstorfer, Generalized eczematous reaction after fractional carbon dioxide laser therapy for tattoo allergy, Journal of Cosmetic and Laser Therapy. 18 (2016) 456-458 DOI: 10.1080/14764172.2016.1225962. [97] O.O. Morais, E.F. Lemos, M.C. Sousa, C.M. Gomes, I.M. Costa, and C.D. Paula, The use of ablative lasers in the treatment of facial melasma, An Bras Dermatol. 88 (2013) 238-42 DOI: 10.1590/s0365-05962013000200009. [98] B. Yalici-Armagan and G. Elcin, Fractional carbon dioxide laser for facial rejuvenation: A prospective study to evaluate the efficacy and the safety, J Cosmet Laser Ther. (2017) 1-7 DOI: 10.1080/14764172.2017.1358453. [99] A. Balzani, R.M. Chilgar, M. Nicoli, S. Sapountzis, D. Lazzeri, V. Cervelli, and F. Nicoli, Novel approach with fractional ultrapulse CO2 laser for the treatment of upper eyelid dermatochalasis and periorbital rejuvenation, Lasers Med. Sci. 28 (2013) 1483-7 DOI: 10.1007/s10103-012-1255-4. [100] M.M. Toyos, Continuous Wave Fractional CO(2) Laser for the Treatment of Upper Eyelid Dermatochalasis and Periorbital Rejuvenation, Photomedicine and laser surgery. 35 (2017) 278-281 DOI: 10.1089/pho.2016.4225. [101] S. del Río-Sancho, C.E. Serna-Jimenez, A. Calatayud-Pascual, C. Balaguer-Fernandez, A. Femenia-Font, V. Merino, and A. Lopez-Castellano, Transdermal Absorption of Memantine. Effect of Chemical Enhancers, Iontophoresis and Role of Enhancer Lipophilicity, Eur. J. Pharm. Biopharm. 82 (2012) 164-170. [102] A.M. Erlendsson, A.G. Doukas, W.A. Farinelli, B. Bhayana, R.R. Anderson, and M. Haedersdal, Fractional laser-assisted drug delivery: Active filling of laser channels with pressure and vacuum alteration, Lasers Surg Med. 48 (2016) 116-24 DOI: 10.1002/lsm.22374. [103] U.H. Olesen, M. Mogensen, and M. Haedersdal, Vehicle type affects filling of fractional laser-ablated channels imaged by optical coherence tomography, Lasers Med Sci. 32 (2017) 679-684 DOI: 10.1007/s10103-017-2168-z. [104] W.R. Lee, S.C. Shen, S.A. Al-Suwayeh, H.H. Yang, Y.C. Li, and J.Y. Fang, Skin permeation of small-molecule drugs, macromolecules, and nanoparticles mediated by a fractional carbon dioxide laser: the role of hair follicles, Pharm Res. 30 (2013) 792-802 DOI: 10.1007/s11095-012-0920-4. [105] W.R. Lee, S.C. Shen, K.H. Wang, C.H. Hu, and J.Y. Fang, The effect of laser treatment on skin to enhance and control transdermal delivery of 5-fluorouracil, J Pharm Sci. 91 (2002) 1613-26 DOI: 10.1002/jps.10142. [106] C.Y. Hsiao, H.C. Sung, S. Hu, and C.H. Huang, Fractional CO2 laser treatment to enhance skin permeation of tranexamic acid with minimal skin disruption, Dermatology. 230 (2015) 269-75 DOI: 10.1159/000371386.

[107] W.R. Lee, S.C. Shen, I.A. Aljuffali, Y.C. Li, and J.Y. Fang, Impact of different vehicles for

Jo

ur

na

lP

re

-p

ro of

laser-assisted drug permeation via skin: full-surface versus fractional ablation, Pharm Res. 31 (2014) 382-93 DOI: 10.1007/s11095-013-1167-4. [108] W.R. Lee, S.C. Shen, W. Kuo-Hsien, C.H. Hu, and J.Y. Fang, Lasers and microdermabrasion enhance and control topical delivery of vitamin C, J Invest Dermatol. 121 (2003) 111825 DOI: 10.1046/j.1523-1747.2003.12537.x. [109] E. Wenande, U.H. Olesen, M.R. Boesen, D.P. Persson, C.M. Lerche, S. Sturup, B. Gammelgaard, S. Husted, R.R. Anderson, and M. Haedersdal, Laser-assisted delivery enhances topical uptake of the anticancer agent cisplatin, Drug Deliv. 25 (2018) 18771885 DOI: 10.1080/10717544.2018.1534896. [110] C.Y. Hsiao, C.H. Huang, S. Hu, Y.S. Ko, H.C. Sung, C.C. Chen, and S.Y. Huang, Fractional carbon dioxide laser treatment to enhance skin permeation of ascorbic acid 2glucoside with minimal skin disruption, Dermatol Surg. 38 (2012) 1284-93 DOI: 10.1111/j.1524-4725.2012.02454.x. [111] C.S. Haak, B. Bhayana, W.A. Farinelli, R.R. Anderson, and M. Haedersdal, The impact of treatment density and molecular weight for fractional laser-assisted drug delivery, J Control Release. 163 (2012) 335-41 DOI: 10.1016/j.jconrel.2012.09.008. [112] W.R. Lee, S.C. Shen, W.Y. Chen, I.A. Aljuffali, S.Y. Suen, and J.Y. Fang, Noninvasive delivery of siRNA and plasmid DNA into skin by fractional ablation: erbium:YAG laser versus CO(2) laser, Eur J Pharm Biopharm. 86 (2014) 315-23 DOI: 10.1016/j.ejpb.2013.08.006. [113] C.S. Haak, W.A. Farinelli, J. Tam, A.G. Doukas, R.R. Anderson, and M. Haedersdal, Fractional laser-assisted delivery of methyl aminolevulinate: Impact of laser channel depth and incubation time, Lasers Surg Med. 44 (2012) 787-95 DOI: 10.1002/lsm.22102. [114] M. Haedersdal, F.H. Sakamoto, W.A. Farinelli, A.G. Doukas, J. Tam, and R.R. Anderson, Pretreatment with ablative fractional laser changes kinetics and biodistribution of topical 5-aminolevulinic acid (ALA) and methyl aminolevulinate (MAL), Lasers Surg Med. 46 (2014) 462-9 DOI: 10.1002/lsm.22259. [115] X. Chen, D. Shah, G. Kositratna, D. Manstein, R.R. Anderson, and M.X. Wu, Facilitation of transcutaneous drug delivery and vaccine immunization by a safe laser technology, J Control Release. 159 (2012) 43-51 DOI: 10.1016/j.jconrel.2012.01.002. [116] B.T. Nguyen, S.D. Gan, N. Konnikov, and C.A. Liang, Treatment of superficial basal cell carcinoma and squamous cell carcinoma in situ on the trunk and extremities with ablative fractional laser-assisted delivery of topical fluorouracil, J Am Acad Dermatol. 72 (2015) 558-60 DOI: 10.1016/j.jaad.2014.11.033. [117] C.S. Haak, K. Togsverd-Bo, D. Thaysen-Petersen, H.C. Wulf, U. Paasch, R.R. Anderson, and M. Haedersdal, Fractional laser-mediated photodynamic therapy of high-risk basal cell carcinomas--a randomized clinical trial, Br J Dermatol. 172 (2015) 215-22 DOI: 10.1111/bjd.13166. [118] P.R. Letada, P.R. Shumaker, and N.S. Uebelhoer, Demonstration of protoporphyrin IX (PpIX) localized to areas of palmar skin injected with 5-aminolevulinic acid (ALA) and pre-treated with a fractionated CO2 laser prior to topically applied ALA, Photodiagnosis and Photodynamic Therapy. 7 (2010) 120-122 DOI: https://doi.org/10.1016/j.pdpdt.2010.02.004. [119] G. Oni, Y. Rasko, and J. Kenkel, Topical lidocaine enhanced by laser pretreatment: a safe and effective method of analgesia for facial rejuvenation, Aesthet Surg J. 33 (2013) 854-61 DOI: 10.1177/1090820x13496248. [120] C. Pestoni Porven, V. Vieira Dos Santos, and J. Del Pozo Losada, Fractional carbon dioxide (CO2) laser combined with topical tretinoin for the treatment of different forms of cystic acne, J Cosmet Laser Ther. 19 (2017) 465-468 DOI: 10.1080/14764172.2017.1349323.

[121] A.A. Meesters, M.J. Nieboer, S. Kezic, M.A. de Rie, and A. Wolkerstorfer, Parameters in

Jo

ur

na

lP

re

-p

ro of

fractional laser assisted delivery of topical anesthetics: Role of laser type and laser settings, Lasers Surg Med. 50 (2018) 813-818 DOI: 10.1002/lsm.22936. [122] J.S. Waibel, A.J. Wulkan, and P.R. Shumaker, Treatment of hypertrophic scars using laser and laser assisted corticosteroid delivery, Lasers Surg Med. 45 (2013) 135-40 DOI: 10.1002/lsm.22120. [123] V. Vachiramon, C. Chaiyabutr, P. Rattanaumpawan, and S. Kanokrungsee, Effects of a preceding fractional carbon dioxide laser on the outcome of combined local narrowband ultraviolet B and topical steroids in patients with vitiligo in difficult-totreat areas, Lasers Surg Med. 48 (2016) 197-202 DOI: 10.1002/lsm.22389. [124] L. Li, Y. Wu, L. Li, Y. Sun, L. Qiu, X.H. Gao, and H.D. Chen, Triple combination treatment with fractional CO2 laser plus topical betamethasone solution and narrowband ultraviolet B for refractory vitiligo: a prospective, randomized half-body, comparative study, Dermatol Ther. 28 (2015) 131-4 DOI: 10.1111/dth.12202. [125] Y. Hilerowicz, A. Koren, J. Mashiah, O. Katz, E. Sprecher, and O. Artzi, Fractional ablative carbon dioxide laser followed by topical sodium stibogluconate application: A treatment option for pediatric cutaneous leishmaniasis, Pediatr Dermatol. 35 (2018) 366-369 DOI: 10.1111/pde.13457. [126] Y. Huang, F. Zhuo, and L. Li, Enhancing hair growth in male androgenetic alopecia by a combination of fractional CO2 laser therapy and hair growth factors, Lasers Med Sci. 32 (2017) 1711-1718 DOI: 10.1007/s10103-017-2232-8. [127] H.I. Gawdat, R.A. Hegazy, M.M. Fawzy, and M. Fathy, Autologous platelet rich plasma: topical versus intradermal after fractional ablative carbon dioxide laser treatment of atrophic acne scars, Dermatol Surg. 40 (2014) 152-61 DOI: 10.1111/dsu.12392. [128] A. Rkein, D. Ozog, and J.S. Waibel, Treatment of atrophic scars with fractionated CO2 laser facilitating delivery of topically applied poly-L-lactic acid, Dermatol Surg. 40 (2014) 624-31 DOI: 10.1111/dsu.0000000000000010. [129] B.H. Mahmoud, C. Burnett, and D. Ozog, Prospective randomized controlled study to determine the effect of topical application of botulinum toxin A for crow's feet after treatment with ablative fractional CO2 laser, Dermatol Surg. 41 Suppl 1 (2015) S75-81 DOI: 10.1097/01.DSS.0000452642.83894.ab. [130] R. Srinivasan, Ablation of polymers and biological tissue by ultraviolet lasers, Science. 234 (1986) 559-65. [131] S.L. Jacques, D.J. McAuliffe, I.H. Blank, and J.A. Parrish, Controlled removal of human stratum corneum by pulsed laser, J Invest Dermatol. 88 (1987) 88-93. [132] Y.N. Kalia, Y.G. Bachhav, T. Bragagna, and C. Bohler, P.L.E.A.S.E. (Painless laser Epidermal System): A new laser microporation technology, Drug Deliv. Technol. 8 (2008) 26-31. [133] M.S. Kaminer, Atlas of Cosmetic Surgery. 2009: Saunders. [134] K.A. Khatri, The effects of variable pulse width of Er:YAG laser on facial skin, Dermatol Surg. 27 (2001) 332-4. [135] E.F. Rostan, R.E. Fitzpatrick, and M.P. Goldman, Laser resurfacing with a long pulse erbium:YAG laser compared to the 950 ms pulsed CO(2) laser, Lasers Surg Med. 29 (2001) 136-41. [136] A.K. Gupta, Clinical Ophthalmology: Contemporary Perspectives. 2012: Elsevier Health Sciences. [137] D.S. Grewal, T. Schultz, S. Basti, and H.B. Dick, Femtosecond laser–assisted cataract surgery—current status and future directions, Survey of Ophthalmology. 61 (2016) 103-131 DOI: https://doi.org/10.1016/j.survophthal.2015.09.002. [138] H.B. Dick, 17 The Basics of Femtosecond Laser Cataract Surgery, in Femtosecond Laser Surgery in Ophthalmology, H.B. Dick, R.D. Gerste, and T. Schultz, Editors. 2018, Georg Thieme Verlag: Stuttgart.

[139] K. Blochowiak, P. Andrysiak, K. Sidorowicz, H. Witmanowski, W. Hedzelek, and J. Sokalski,

Jo

ur

na

lP

re

-p

ro of

Selected applications of Er:YAG and CO2 lasers for treatment of benign neoplasms and tumorous lesions in the mouth, Postepy Dermatol Alergol. 32 (2015) 337-43 DOI: 10.5114/pdia.2015.48053. [140] J.L. Cohen, Minimizing skin cancer surgical scars using ablative fractional Er:YAG laser treatment, J Drugs Dermatol. 12 (2013) 1171-3. [141] F.W. Neukam and F. Stelzle, Laser tumor treatment in oral and maxillofacial surgery, Physics Procedia. 5 (2010) 91-100 DOI: https://doi.org/10.1016/j.phpro.2010.08.125. [142] O.A. Ibrahimi, Z. Syed, F.H. Sakamoto, M.M. Avram, and R.R. Anderson, Treatment of tattoo allergy with ablative fractional resurfacing: A novel paradigm for tattoo removal, Journal of the American Academy of Dermatology. 64 (2011) 1111-1114 DOI: https://doi.org/10.1016/j.jaad.2010.11.005. [143] K. Sardana, R. Ranjan, A.M. Kochhar, K.G. Mahajan, and V.K. Garg, A rapid tattoo removal technique using a combination of pulsed Er:YAG and Q-Switched Nd:YAG in a split lesion protocol, J Cosmet Laser Ther. 17 (2015) 177-83 DOI: 10.3109/14764172.2015.1007066. [144] A.l. Tarijian and D.J. Goldberg, Fractional ablative laser skin resurfacing: A review, Journal of Cosmetic and Laser Therapy. 13 (2011) 262-264 DOI: 10.3109/14764172.2011.630083. [145] J.M. Lee, I.H. Kim, I.J. Rhyu, and H.J. Ryu, Combined intense pulsed light and Er:YAG laser treatment of congenital melanocytic nevus, J Cosmet Laser Ther. 17 (2015) 162-4 DOI: 10.3109/14764172.2014.1003244. [146] E. Remlova, T. Dostalova, I. Michalusova, J. Vranova, L. Navratil, and J. Rosina, Hemangioma curative effect of PDL, alexandrite, Er:YAG and CO(2) lasers, Photomed Laser Surg. 29 (2011) 815-25 DOI: 10.1089/pho.2011.3058. [147] E. Azma and M. Razaghi, Laser Treatment of Oral and Maxillofacial Hemangioma, Journal of lasers in medical sciences. 9 (2018) 228-232 DOI: 10.15171/jlms.2018.41. [148] J.H. Lee, H.E. Lee, Y. Lee, Y.J. Seo, J.H. Lee, and M. Im, Er:YAG laser treatment of epidermal nevus syndrome, Int J Dermatol. 56 (2017) e13-e15 DOI: 10.1111/ijd.13417. [149] E.L. Maranda, L. Akintilo, K. Hundley, A.H. Nguyen, K.J. Moore, J. Zullo, and J.J. Jimenez, Laser therapy for the treatment of pearly penile papules, Lasers Med Sci. 32 (2017) 243-248 DOI: 10.1007/s10103-016-2065-x. [150] M.S. Gurel and B.B. Aral, Effectiveness of erbium:YAG laser and cryosurgery in seborrheic keratoses: Randomized, prospective intraindividual comparison study, Journal of Dermatological Treatment. 26 (2015) 477-480 DOI: 10.3109/09546634.2015.1024597. [151] A. Balevi, P. Ustuner, and M. Ozdemir, Use of Er:YAG for the treatment of recalcitrant facial verruca plana, J Dermatolog Treat. 28 (2017) 368-371 DOI: 10.1080/09546634.2016.1244601. [152] J. Nguyen, D.Z. Korta, L.W. Chapman, and K.M. Kelly, Laser Treatment of Nongenital Verrucae: A Systematic Review, JAMA Dermatol. 152 (2016) 1025-34 DOI: 10.1001/jamadermatol.2016.0826. [153] M. Venkataram, ACS(I) Textbook on Cutaneous & Aesthetic Surgery: Two Volume Set. 2017: Jaypee Brothers,Medical Publishers Pvt. Limited. [154] P.S. Hughes and A.P. Hughes, Absence of human papillomavirus DNA in the plume of erbium:YAG laser-treated warts, J Am Acad Dermatol. 38 (1998) 426-8. [155] R.M. Robati, E. Asadi, A. Shafiee, N. Namazi, and A. Talebi, Efficacy of long pulse Nd:YAG laser versus fractional Er:YAG laser in the treatment of hand wrinkles, Lasers Med Sci. (2017) DOI: 10.1007/s10103-017-2351-2. [156] K.H. Chen, K.W. Tam, I.F. Chen, S.K. Huang, P.C. Tzeng, H.J. Wang, and C.C. Chen, A systematic review of comparative studies of CO2 and erbium:YAG lasers in resurfacing facial rhytides (wrinkles), J Cosmet Laser Ther. 19 (2017) 199-204 DOI: 10.1080/14764172.2017.1288261.

[157] R.M. Robati and E. Asadi, Efficacy and safety of fractional CO2 laser versus fractional

Jo

ur

na

lP

re

-p

ro of

Er:YAG laser in the treatment of facial skin wrinkles, Lasers Med Sci. 32 (2017) 283-289 DOI: 10.1007/s10103-016-2111-8. [158] S.J. Lee, J.M. Kim, Y.K. Kim, S.J. Seo, and K.Y. Park, The pinhole method using an erbium: YAG laser for the treatment of papular acne scars, Dermatol Ther. 30 (2017) DOI: 10.1111/dth.12512. [159] M.A. Osman, H.A. Shokeir, and M.M. Fawzy, Fractional Erbium-Doped Yttrium Aluminum Garnet Laser Versus Microneedling in Treatment of Atrophic Acne Scars: A Randomized Split-Face Clinical Study, Dermatol Surg. 43 Suppl 1 (2017) S47-s56 DOI: 10.1097/dss.0000000000000951. [160] A. Firooz, A. Rajabi-Estarabadi, and M.H. Nassiri-Kashani, Treatment of atrophic facial acne scars with fractional Er:YAG laser in skin phototype III-IV: A pilot study, J Cosmet Laser Ther. 18 (2016) 204-7 DOI: 10.3109/14764172.2016.1157354. [161] C.C. Dierickx, K.A. Khatri, Z.S. Tannous, J.J. Childs, R.H. Cohen, A. Erofeev, D. Tabatadze, I.V. Yaroslavsky, and G.B. Altshuler, Micro-fractional ablative skin resurfacing with two novel erbium laser systems, Lasers Surg Med. 40 (2008) 113-23 DOI: 10.1002/lsm.20601. [162] J. Yu, Y.G. Bachhav, S. Summer, A. Heinrich, T. Bragagna, C. Bohler, and Y.N. Kalia, Using controlled laser-microporation to increase transdermal delivery of prednisone, J Control Release. 148 (2010) e71-3 DOI: 10.1016/j.jconrel.2010.07.032. [163] Y.G. Bachhav, A. Heinrich, and Y.N. Kalia, Using laser microporation to improve transdermal delivery of diclofenac: Increasing bioavailability and the range of therapeutic applications, Eur. J. Pharm. Biopharm. 78 (2011) 408-414 DOI: 10.1016/j.ejpb.2011.03.006. [164] Y.G. Bachhav, S. Summer, A. Heinrich, T. Bragagna, C. Bohler, and Y.N. Kalia, Effect of controlled laser microporation on drug transport kinetics into and across the skin, J. Control. Release. 146 (2010) 31-36 DOI: 10.1016/j.jconrel.2010.05.025. [165] E.H. Taudorf, C.M. Lerche, A.M. Erlendsson, P.A. Philipsen, S.H. Hansen, C. Janfelt, U. Paasch, R.R. Anderson, and M. Haedersdal, Fractional laser-assisted drug delivery: Laser channel depth influences biodistribution and skin deposition of methotrexate, Lasers Surg Med. 48 (2016) 519-29 DOI: 10.1002/lsm.22484. [166] S. del Río-Sancho, C. Cros, B. Coutaz, M. Cuendet, and Y.N. Kalia, Cutaneous iontophoresis of mu-conotoxin CnIIIC-A potent NaV1.4 antagonist with analgesic, anaesthetic and myorelaxant properties, Int J Pharm. 518 (2016) 59-65 DOI: 10.1016/j.ijpharm.2016.12.054. [167] J. Khamthara, C. Kumtornrut, K. Pongpairoj, and P. Asawanonda, Silicone gel enhances the efficacy of Er:YAG laser treatment for atrophic acne scars: A randomized, split-face, evaluator-blinded, placebo-controlled, comparative trial, J Cosmet Laser Ther. (2017) 1-6 DOI: 10.1080/14764172.2017.1376095. [168] L. Engelke, G. Winter, and J. Engert, Application of water-soluble polyvinyl alcohol-based film patches on laser microporated skin facilitates intradermal macromolecule and nanoparticle delivery, Eur J Pharm Biopharm. 128 (2018) 119-130 DOI: 10.1016/j.ejpb.2018.04.008. [169] E.A. Genina, Y.I. Svenskaya, I.Y. Yanina, L.E. Dolotov, N.A. Navolokin, A.N. Bashkatov, G.S. Terentyuk, A.B. Bucharskaya, G.N. Maslyakova, D.A. Gorin, V.V. Tuchin, and G.B. Sukhorukov, In vivo optical monitoring of transcutaneous delivery of calcium carbonate microcontainers, Biomedical Optics Express. 7 (2016) 2082-2087 DOI: 10.1364/BOE.7.002082. [170] M. Singhal, S. del Río-Sancho, K. Sonaje, and Y.N. Kalia, Fractional Laser Ablation for the Cutaneous Delivery of Triamcinolone Acetonide from Cryomilled Polymeric Microparticles: Creating Intraepidermal Drug Depots, Mol. Pharm. 13 (2016) 500–511 DOI: 10.1021/acs.molpharmaceut.5b00711.

[171] E.A. Genina, A.N. Bashkatov, L.E. Dolotov, G.N. Maslyakova, V.I. Kochubey, I.V.

Jo

ur

na

lP

re

-p

ro of

Yaroslavsky, G.B. Altshuler, and V.V. Tuchin. Transcutaneous delivery of micro- and nanoparticles with laser microporation. 2013. SPIE. [172] S. Gou, S. del Rio-Sancho, M. Singhal, H.-J. Laubach, and Y.N. Kalia, Er:YAG fractional laser ablation for cutaneous co-delivery of pentoxifylline and d-α-tocopherol succinate: A new approach for topical treatment of radiation-induced skin fibrosis, European Journal of Pharmaceutical Sciences. (2019) DOI: https://doi.org/10.1016/j.ejps.2019.05.007. [173] B. Zorec, D. Skrabelj, M. Marincek, D. Miklavcic, and N. Pavselj, The effect of pulse duration, power and energy of fractional Er:YAG laser for transdermal delivery of differently sized FITC dextrans, Int J Pharm. 516 (2017) 204-213 DOI: 10.1016/j.ijpharm.2016.10.060. [174] W.R. Lee, S.C. Shen, S.A. Al-Suwayeh, H.H. Yang, C.Y. Yuan, and J.Y. Fang, Laser-assisted topical drug delivery by using a low-fluence fractional laser: imiquimod and macromolecules, J Control Release. 153 (2011) 240-8 DOI: 10.1016/j.jconrel.2011.03.015. [175] J. Yu, D.R. Kalaria, and Y.N. Kalia, Erbium:YAG fractional laser ablation for the percutaneous delivery of intact functional therapeutic antibodies, J Control Release. 156 (2011) 53-9 DOI: 10.1016/j.jconrel.2011.07.024. [176] W.-R. Lee, T.-L. Pan, P.-W. Wang, R.-Z. Zhuo, C.-M. Huang, and J.-Y. Fang, Erbium:YAG laser enhances transdermal peptide delivery and skin vaccination, Journal of Controlled Release. 128 (2008) 200-208 DOI: https://doi.org/10.1016/j.jconrel.2008.03.003. [177] H.J. Lee, N. Choi, E.-S. Yoon, and I.-J. Cho, MEMS devices for drug delivery, Advanced Drug Delivery Reviews. 128 (2018) 132-147 DOI: https://doi.org/10.1016/j.addr.2017.11.003. [178] C. Cullander and R.H. Guy, (D) Routes of delivery: Case studies: (6) Transdermal delivery of peptides and proteins, Advanced Drug Delivery Reviews. 8 (1992) 291-329 DOI: https://doi.org/10.1016/0169-409X(92)90006-C. [179] H.S. Kim, X. Sun, J.-H. Lee, H.-W. Kim, X. Fu, and K.W. Leong, Advanced drug delivery systems and artificial skin grafts for skin wound healing, Advanced Drug Delivery Reviews. (2018) DOI: https://doi.org/10.1016/j.addr.2018.12.014. [180] N. Dragicevic and H. Maibach, Combined use of nanocarriers and physical methods for percutaneous penetration enhancement, Advanced Drug Delivery Reviews. 127 (2018) 58-84 DOI: https://doi.org/10.1016/j.addr.2018.02.003. [181] Q. Liu, M. Das, Y. Liu, and L. Huang, Targeted drug delivery to melanoma, Advanced Drug Delivery Reviews. 127 (2018) 208-221 DOI: https://doi.org/10.1016/j.addr.2017.09.016. [182] B. Forster, A. Klein, R.M. Szeimies, and T. Maisch, Penetration enhancement of two topical 5-aminolaevulinic acid formulations for photodynamic therapy by erbium:YAG laser ablation of the stratum corneum: continuous versus fractional ablation, Exp Dermatol. 19 (2010) 806-12 DOI: 10.1111/j.1600-0625.2010.01093.x. [183] W.R. Lee, S.C. Shen, I.A. Aljuffali, Y.C. Li, and J.Y. Fang, Erbium-yttrium-aluminum-garnet laser irradiation ameliorates skin permeation and follicular delivery of antialopecia drugs, J Pharm Sci. 103 (2014) 3542-3552 DOI: 10.1002/jps.24143. [184] W.R. Lee, S.C. Shen, C.L. Fang, C.R. Liu, and J.Y. Fang, Skin pretreatment with an Er:YAG laser promotes the transdermal delivery of three narcotic analgesics, Lasers Med Sci. 22 (2007) 271-8 DOI: 10.1007/s10103-007-0452-z. [185] W.R. Lee, S.C. Shen, H.H. Lai, C.H. Hu, and J.Y. Fang, Transdermal drug delivery enhanced and controlled by erbium:YAG laser: a comparative study of lipophilic and hydrophilic drugs, J Control Release. 75 (2001) 155-66.

[186] A.M. Erlendsson, E.H. Taudorf, A.H. Eriksson, C.S. Haak, J.R. Zibert, U. Paasch, R.R.

Jo

ur

na

lP

re

-p

ro of

Anderson, and M. Haedersdal, Ablative fractional laser alters biodistribution of ingenol mebutate in the skin, Arch Dermatol Res. 307 (2015) 515-22 DOI: 10.1007/s00403-0151561-3. [187] W.R. Lee, S.C. Shen, C.R. Liu, C.L. Fang, C.H. Hu, and J.Y. Fang, Erbium:YAG laser-mediated oligonucleotide and DNA delivery via the skin: an animal study, J Control Release. 115 (2006) 344-53 DOI: 10.1016/j.jconrel.2006.08.012. [188] Y.G. Bachhav, A. Heinrich, and Y.N. Kalia, Controlled intra- and transdermal protein delivery using a minimally invasive Erbium:YAG fractional laser ablation technology, Eur. J. Pharm. Biopharm. 84 (2013) 355-364 DOI: 10.1016/j.ejpb.2012.11.018. [189] X. Zhang, H. Jiang, Y. Zhang, G. Ren, L. Dong, J. Zhu, Y. Tu, J. Tao, and L. Yang, Transdermal delivery of water-soluble fluorescent antibody mediated by fractional Er:YAG laser for the diagnosis of lupus erythematosus in mice, Lasers Surg Med. 51 (2019) 268-277 DOI: 10.1002/lsm.23047. [190] M. Lapteva, S. del Río-Sancho, E. Wu, W. Shawn Carbonell, C. Böhler, and Y.N. Kalia, Fractional laser ablation for the targeted cutaneous delivery of an anti-CD29 monoclonal antibody – OS2966, Scientific Reports. 9 (2019) 1-12 DOI: 10.1038/s41598018-36966-0. [191] S. Scheiblhofer, A. Strobl, V. Hoepflinger, T. Thalhamer, M. Steiner, J. Thalhamer, and R. Weiss, Skin vaccination via fractional infrared laser ablation - Optimization of laserparameters and adjuvantation, Vaccine. 35 (2017) 1802-1809 DOI: https://doi.org/10.1016/j.vaccine.2016.11.105. [192] F. Mokhtari, A. Bostakian, Z. Shahmoradi, T. Jafari-Koshki, F. Iraji, G. Faghihi, S.M. Hosseini, and B. Bafandeh, Potential emerging treatment in vitiligo using Er:YAG in combination with 5FU and clobetasol, J Cosmet Dermatol. (2017) DOI: 10.1111/jocd.12373. [193] C.S. Haak, K. Christiansen, A.M. Erlendsson, E.H. Taudorf, D. Thaysen-Petersen, H.C. Wulf, and M. Haedersdal, Ablative fractional laser enhances MAL-induced PpIX accumulation: Impact of laser channel density, incubation time and drug concentration, Journal of Photochemistry and Photobiology B: Biology. 159 (2016) 4248 DOI: https://doi.org/10.1016/j.jphotobiol.2016.03.021. [194] S.M. Park, G.W. Kim, J.H. Mun, M. Song, H.S. Kim, B.S. Kim, M.B. Kim, and H.C. Ko, Fractional Laser-Assisted Topical Imiquimod 5% Cream Treatment for Recalcitrant Common Warts in Children: A Pilot Study, Dermatol Surg. 42 (2016) 1340-1346 DOI: 10.1097/dss.0000000000000885. [195] R. Li, J. Zhou, H. Su, M. Wang, Y. Wang, S. Xiao, and H. Ma, 2940-nm Er:YAG fractional laser enhanced the effect of topical drug for psoriasis, Lasers Med Sci. 32 (2017) 13931397 DOI: 10.1007/s10103-017-2259-x. [196] U. Wollina, Er:YAG laser followed by topical podophyllotoxin for hard-to-treat palmoplantar warts, J Cosmet Laser Ther. 5 (2003) 35-7. [197] Z. Oesterreicher, E. Lackner, W. Jager, M. Hoferl, and M. Zeitlinger, Lack of dermal penetration of topically applied gentamicin as pharmacokinetic evidence indicating insufficient efficacy, J Antimicrob Chemother. 73 (2018) 2823-2829 DOI: 10.1093/jac/dky274. [198] R. Yan, J. Yuan, H. Chen, Y.H. Li, Y. Wu, X.H. Gao, and H.D. Chen, Fractional Er:YAG laser assisting topical betamethasone solution in combination with NB-UVB for resistant non-segmental vitiligo, Lasers Med Sci. 32 (2017) 1571-1577 DOI: 10.1007/s10103017-2282-y. [199] K. Greveling, E.P. Prens, and M.B. van Doorn, Treatment of port wine stains using Pulsed Dye Laser, Erbium YAG Laser, and topical rapamycin (sirolimus)-A randomized controlled trial, Lasers Surg Med. 49 (2017) 104-109 DOI: 10.1002/lsm.22548.

[200] J. Shen, X.G. Lu, J.J. Jin, and H.W. Wang, Combination of a 2940 nm Er:YAG laser with

Jo

ur

na

lP

re

-p

ro of

recombinant bovine basic fibroblast growth factor (rb-bFGF) and light-emitting diodered light (LED-RL) for the treatment of striae alba: A pilot study, J Cosmet Dermatol. (2017) DOI: 10.1111/jocd.12376. [201] E. Carome, N. Clark, and C. Moeller, Generation of Acoustic Signals in Liquids by Ruby Laser-Induced Thermal Stress Transients, Appl. Phys. Lett. 4 (1964) 95-97. [202] G.K. Menon, N. Kollias, and A.G. Doukas, Ultrastructural Evidence of Stratum Corneum Permeabilization Induced by Photomechanical Waves, Journal of Investigative Dermatology. 121 (2003) 104-109 DOI: https://doi.org/10.1046/j.15231747.2003.12302.x. [203] A. Doukas and T.J. Flotte, Physical characteristics and biological effects of laser-induced stress waves, Ultrasound in Med. & Biol. 22 (1996) 151-164. [204] S. Fassbender, B. Hoffmann, and W. Arnold, Efficient generation of acoustic pressure waves by short laser pulses, Materials Science and Engineering: A. 122 (1989) 37-41 DOI: https://doi.org/10.1016/0921-5093(89)90768-5. [205] L. Yang, Stress waves generated in thin metallic films by a Q‐switched ruby laser, J. Appl. Phys. 45 (1974) 2601-2608. [206] H. Fukumura, N. Mibuka, S. Eura, and H. Masuhara, Mass spectrometric studies on laser ablation of polystyrene sensitized with anthracene, J. Phys. Chem. 97 (1993) 1376113766 DOI: 10.1021/j100153a053. [207] E. Biagi, M. Brenci, S. Fontani, L. Masotti, and M. Pieraccini, Photoacoustic Generation: Optical Fiber Ultrasonic Sources for Non-Destructive Evaluation and Clinical Diagnosis, Optical Review. 4 (1997) 481-483 DOI: 10.1007/s10043-997-0481-7. [208] E. Biagi, F. Margheri, and D. Menichelli, Efficient laser-ultrasound generation by using heavily absorbing films as targets, IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 48 (2001) 1669-80. [209] Y. Guo, H.W. Baac, S.-L. Chen, T.B. Norris, and L.J. Guo. Broad-band, high-efficiency optoacoustic generation using a novel photonic crystal-metallic structure. in Proc. SPIE. 2011. [210] L. Xiong, J.M. Ruddock, and G.J. Diebold, Photoacoustic transients generated by laser irradiation of thin films, Photoacoustics. 3 (2015) 60-63 DOI: https://doi.org/10.1016/j.pacs.2015.02.003. [211] S. Lee, D.J. McAuliffe, T.J. Flotte, N. Kollias, and A.G. Doukas, Photomechanical transdermal delivery: the effect of laser confinement, Lasers Surg Med. 28 (2001) 3447 DOI: 10.1002/lsm.1060. [212] D.J. Goldberg, Laser Treatment of Pigmented Lesions, Dermatologic Clinics. 15 (1997) 397407 DOI: https://doi.org/10.1016/S0733-8635(05)70449-6. [213] T.H. Maiman, Biomedical lasers evolve toward clinical applications, Hosp Manage. 101 (1966) 39-41. [214] C.J. Chang and C.S. Kou, Comparing the effectiveness of Q-switched Ruby laser treatment with that of Q-switched Nd:YAG laser for oculodermal melanosis (Nevus of Ota), J Plast Reconstr Aesthet Surg. 64 (2011) 339-45 DOI: 10.1016/j.bjps.2010.05.036. [215] J.K. Henley and M.L. Ramsey, Tattoo Lasers, in StatPearls. 2017, StatPearls Publishing LLC.: Treasure Island (FL). [216] N.L. Schoenewolf, J. Hafner, R. Dummer, and I. Bogdan Allemann, Laser treatment of solar lentigines on dorsum of hands: QS Ruby laser versus ablative CO2 fractional laser - a randomized controlled trial, Eur J Dermatol. 25 (2015) 122-6 DOI: 10.1684/ejd.2014.2513. [217] H.P. Berlien, H. Breuer, G.J. Müller, N. Krasner, T. Okunata, and D. Sliney, Applied Laser Medicine. 2012: Springer Berlin Heidelberg. [218] B. Chandrashekar, IADVL Textbook of Trichology. 2018: Jaypee Brothers,Medical Publishers Pvt. Limited.

[219] K. Lahiri, Textbook of Lasers in Dermatology. 2016: Jaypee Brothers,Medical Publishers

Jo

ur

na

lP

re

-p

ro of

Pvt. Limited. [220] W.R. Lee, S.C. Shen, R.Z. Zhuo, K.C. Wang, and J.Y. Fang, Enhancement of topical small interfering RNA delivery and expression by low-fluence erbium:YAG laser pretreatment of skin, Hum Gene Ther. 20 (2009) 580-8 DOI: 10.1089/hum.2008.156. [221] G.F. Sá, C. Serpa, and L.G. Arnaut, Stratum corneum permeabilization with photoacoustic waves generated by piezophotonic materials, J. Control. Release. 167 (2013) 290-300 DOI: 10.1016/j.jconrel.2013.02.005. [222] S. Lee, D.J. McAuliffe, N. Kollias, T.J. Flotte, and A.G. Doukas, Permeabilization and recovery of the stratum corneum in vivo: the synergy of photomechanical waves and sodium lauryl sulfate, Lasers Surg Med. 29 (2001) 145-50. [223] S. Lee, D.J. McAuliffe, S.E. Mulholland, and A.G. Doukas, Photomechanical transdermal delivery of insulin in vivo, Lasers Surg. Med. 28 (2001) 282-285 DOI: 10.1002/lsm.1052. [224] M.J. Freire Dos Santos, R. Carvalho, and L.G. Arnaut, Split-Face, Randomized, PlaceboControlled, Double-Blind Study to Investigate Passive Versus Active Dermal Filler Administration, Aesthetic Plast Surg. 42 (2018) 1655-1663 DOI: 10.1007/s00266-0181208-9. [225] G.F. Sá, C. Serpa, and L.G. Arnaut, Photoacoustic Waves as a Skin Permeation Enhancement Method, in Percutaneous Penetration Enhancers Physical Methods in Penetration Enhancement. 2017, Springer. p. 175-191. [226] S. Gonzalez, S. Lee, E. Gonzalez, and A.G. Doukas, Rapid allergen delivery with photomechanical waves for inducing allergic skin reactions in the hairless guinea pig animal model, Am J Contact Dermat. 12 (2001) 162-5. [227] S. Lee, D.J. McAuliffe, T.J. Flotte, N. Kollias, and A.G. Doukas, Photomechanical Transcutaneous Delivery of Macromolecules, Journal of Investigative Dermatology. 111 (1998) 925-929 DOI: https://doi.org/10.1046/j.1523-1747.1998.00415.x. [228] S. Lee, D.J. McAuliffe, N. Kollias, T.J. Flotte, and A.G. Doukas, Photomechanical delivery of 100-nm microspheres through the stratum corneum: implications for transdermal drug delivery, Lasers Surg Med. 31 (2002) 207-10 DOI: 10.1002/lsm.10099. [229] S. Lee, N. Kollias, D.J. McAuliffe, T.J. Flotte, and A.G. Doukas, Topical Drug Delivery in Humans with a Single Photomechanical Wave, Pharmaceutical Research. 16 (1999) 1717-1721 DOI: 10.1023/a:1018954015441. [230] P.J.D. Whiteside, C. Qian, N. Golda, and H.K. Hunt, Ultrasonic modulation of tissue optical properties in ex vivo porcine skin to improve transmitted transdermal laser intensity, Lasers Surg Med. 49 (2017) 666-674 DOI: 10.1002/lsm.22662. [231] Q. Reports, Global Dermatology Laser Market Professional Survey Report 2018. p. 104.