- Email: [email protected]
Nano modified SLA process for titanium implants
Materials Letters 186 (2017) 38–41
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Nano modified SLA process for titanium implants ⁎
Youneng Xie, Jiaxin Li, Z.M. Yu , Qiuping Wei
crossmark
School of Materials Science and Engineering, Central South University, Changsha 410083, PR China
A R T I C L E I N F O
A BS T RAC T
Keywords: Biomaterials Surfaces Corrosion Microstructure
Nano structures gain great prevalence in titanium implants for its enhancement on cell differentiation and gene expression. And sandblast and acid etching (SLA), which yields micro/submicron structures, is the most popular treatment to titanium implants. Aimed at adding nano structures on SLA surfaces, a combination of SLA and H2O2 etching method is proposed. Surface morphology, roughness, surface chemistry and contact angle are characterized. Typical SLA morphology accompanied with nano pits is obtained. Reactive oxygen species are also detected on this surface with remarkable wettability. This novel surface may be promising to dental implants.
1. Introduction
2. Experimental details
Sandblast and acid-etched (SLA) has become the most prevalent surface treatment to titanium implants for its micro/submicron hierarchical structures over the past several decades [1–4]. On one hand, hierarchical structures can enlarge the contact area of titanium, which favors the adhesion, proliferation and differentiation of osteoblasts. On the other hand, they can also improve the mechanical lock on implants-bone interface, thus enhancing the initial fixation of the implants [2,5]. Nano structures attract a substantial amount of attention for their resplendent performances in many aspects especially in biomedical applications [3,5–13]. Many researchers claimed that nano structures on titanium surface can promote osteogenic differentiation. Someone even put that nano structures can improve the antimicrobial properties and decontamination function of implants. Traditional methods to prepare nano structures are anodic oxidation, plasma treatment, and the like, which is either environmentally unfriendly or expensive. Traditional SLA surface impedes the differentiation of osteoblasts and the initial fixation of the implants for the lack of nano structures. Moreover, traditional SLA surface is hydrophobic, which is unfavorable to cell attachment, let alone the differentiation. So some possible measurements should be made to modify SLA process. H2O2 is a wonderful etchant to titanium, and O22− is a hydrophilic group which can also prohibit bacterial breeding. In this study, H2O2 is used to etch SLA titanium surface, aiming at compositing nano structures with SLA surface, which may be a cheap and eco-friendly method for modifying SLA process.
2.1. Corrosion process TA2 commercial titanium plate was cut into disks (Φ15 mm) and then mirror polished to Ra < 0.5 µm. Disks were sandblasted by Al2O3 (Φ250~500 µm) at a pressure of 3 atm. Blasted disks were pretreated in a mixture of HNO3 and HF and subsequently etched in a boiling mixture of H2SO4 and HCl for several minutes and finally immersed in concentrated H2O2 for 1 h. All the samples were ultrasonically cleaned in distilled water, acetone and ultrapure water 10 min three times respectively at the end of each step. Samples were finally rinsed in ultrapure water and dried in hot air. 2.2. Materials characterization Surface morphology was observed by Scanning electron microscopy (SEM, Nova NanoSEM 230). Surface roughness was calculated by surface profiler (Dektak 150 surface profiler) with each testing line of 1000 µm. Surface chemistry was detected using X-ray photoelectron spectroscopy (XPS, ESCALAB 250Xi) with Al Kα irradiation. The binding energies for each spectrum were calibrated based on the C1s spectra of 285.0 eV. Contact angle was tested by sessile drop method. 3. Results and discussion 3.1. Surface morphology Fig. 1 shows the surface morphologies of SLA and nano-modified
⁎
Corresponding author. E-mail address: [email protected] (Z.M. Yu).
http://dx.doi.org/10.1016/j.matlet.2016.08.079 Received 3 June 2016; Received in revised form 10 August 2016; Accepted 14 August 2016 Available online 15 August 2016 0167-577X/ © 2016 Published by Elsevier B.V.
Materials Letters 186 (2017) 38–41
Y. Xie et al.
Fig. 1. Surface topography of SLA (A and C) and NSLA (B and D) titanium.
Fig. 2. XPS spectra of SLA surface (y01) and NSLA surface (y02).
39
Materials Letters 186 (2017) 38–41
Y. Xie et al.
Fig. 3. Surface profiler test results of SLA and NSLA titanium surface.
Fig. 4. Water contact angle on titanium: A) SLA, B) NSLA.
524 eV disappeared after treated in H2O2, indicating that the oxide layer on NSLA surface was thicker than SLA surface, which is beyond the critical thickness of XPS. Thicker oxide layer may also be the explanation to the disappearance of S on NSLA surface.
SLA (NSLA) titanium, from which we can see that these two surfaces show typical SLA morphologies (honeycomb-like holes with diameters ranging from 1 to 5 µm), and they are nearly the same in micro scale except fuzzy and blunt edges and some fine holes on NSLA surface. But many nano pits with diameters of tens of nanometers appear on NSLA surface when it comes to nano scale. The topography of SLA titanium in this experiment resembles that of ITI implants', which may show similar cell responses. And the nano pits on NSLA surface may favor the osteogenic differentiation of cells cultured on it. Meanwhile, nano structures on titanium surfaces can promote their microbial properties [5,14].
3.3. Surface roughness Fig. 3 shows the surface profiler results of these two specimens, and no obvious differences can be seen between them. The average surface roughness is 3.39 µm and 3.35 µm for SLA and NSLA titanium, which are also nearly the same. These results mean that H2O2 only digs nano structures on SLA surface, which is in accordance with the results in Section 3.1.
3.2. Surface chemistry Fig. 2 depicts the XPS spectra of SLA and NSLA titanium surfaces, from which we can see that both these two surfaces contain Ti, C and O, while litter S vestigital is detected only on SLA surface. C1s spectra of these two samples are nearly the same, and they can be fitted by three peaks. The peak centered at 285.0 eV can be identified as C–H or C–C component on the samples. The peak set at 286.5 eV for C=O, and peak at 289 eV for O–C=O. The O1s spectrum of SLA titanium can be postulated to be TiO2, OH and H2O corresponding to the peaks centered at 530 eV, 531.5 eV and 532.5 eV, respectively. While there is another more peak centered at 533.5 eV in the O1s spectrum of NSLA titanium, which may be O22− group due to the formation of Ti(H2O2)24+ after treated in H2O2. It is reported that O22− can significantly improve antimicrobial performance and wettability of implants through providing sustainable O, which can eventually improve initial fixation of implants. Meanwhile, from the spectra of Ti2p (Supplementary 1) we can see that the peak centered at about
3.4. Surface wettability Fig. 4 shows the contact angles of water on these two samples. From Fig. 4 we can see that contact angles are about 121° and 62.8° for SLA and NSLA titanium, respectively, which indicates a much better wettability of NSLA, and this verifies the speculation in Section 3.2. Lower contact angle of NSLA surface can be ascribed to two aspects. One is that some hydrophilic groups remained after treated in H2O2, which improves the polarization of NSLA surface. The other is the capillary effects of nano pits on NSLA surface. Wettability of biomaterials determines the biological cascade of events at the biomaterial/ host interface [15]. Hydrophilic surface favors the adsorption of protein and adherence of osteoblasts, which promotes the initial fixation of implant, thus shortening the course. Traditional SLA surface is likely to become hydrophobic when stored in atmosphere. This result indicates that H2O2 treatment may be a promising method for 40
Materials Letters 186 (2017) 38–41
Y. Xie et al.
improving the wettability of SLA surface. [3]
4. Conclusion A novel surface combining traditional SLA micron morphology with nano structures was produced by adding a simple, cheap and ecofriendly procedure to traditional SLA process. SLA and NSLA show similar morphology and surface roughness. H2O2 removes the S residual on SLA surface, and increases the oxide layer thickness. Meanwhile, O22− group vestigital was also detected on NSLA surface. Moreover, H2O2 treatment turned hydrophobic SLA surface to hydrophilic surface, which may greatly enhance the biomedical performance in a cascade of aspects. This novel surface is very promising in implant application. And this method is of great significance to traditional SLA modification.
[4]
[5]
[6]
[7]
[8] [9]
Acknowledgment [10]
We gratefully acknowledge the National Natural Foundation of China (No. 51301211) for financial support.
Science [11]
Appendix A. Supporting information [12]
Supplementary data associated with this article can be found in the online version at doi:10.1016/j.matlet.2016.08.079.
[13]
References [14] [1] R.A. Gittens, R. Olivares-Navarrete, A. Cheng, D.M. Anderson, T. McLachlan, I. Stephan, J. Geis-Gerstorfer, K.H. Sandhage, A.G. Fedorov, F. Rupp, et al., The roles of titanium surface micro/nanotopography and wettability on the differential response of human osteoblast lineage cells, Acta Biomater. 9 (4) (2013) 6268–6277. [2] Z. Qu, X. Rausch-Fan, M. Wieland, M. Matejka, A. Schedle, The initial attachment
[15]
41
and subsequent behavior regulation of osteoblasts by dental implant surface modification, J. Biomed. Mater. Res. Part A 82A (3) (2007) 658–668. Q.-L. Ma, L.-Z. Zhao, R.-R. Liu, B.-Q. Jin, W. Song, Y. Wang, Y.-S. Zhang, L.H. Chen, Y.-M. Zhang, Improved implant osseointegration of a nanostructured titanium surface via mediation of macrophage polarization, Biomaterials 35 (37) (2014) 9853–9867. B.S. Kopf, A. Schipanski, M. Rottmar, S. Berner, K. Maniura-Weber, Enhanced differentiation of human osteoblasts on Ti surfaces pre-treated with human whole blood, Acta Biomater. 19 (2015) 180–190. Y. Shibata, Y. Tanimoto, A review of improved fixation methods for dental implants. Part I: Surface optimization for rapid osseointegration, J. Prosthodont. Res. 59 (1) (2015) 20–33. O. Akhavan, E. Ghaderi, Self-accumulated Ag nanoparticles on mesoporous TiO2 thin film with high bactericidal activities, Surf. Coat. Technol. 204 (21–22) (2010) 3676–3683. E.-J. Lee, J.-S. Kwon, S.-H. Uhm, D.-H. Song, Y.H. Kim, E.H. Choi, K.-N. Kim, The effects of non-thermal atmospheric pressure plasma jet on cellular activity at SLAtreated titanium surfaces, Curr. Appl. Phys. 13 (Suppl. 1) (2013) S36–S41. H. Liu, T.J. Webster, Nanomedicine for implants: a review of studies and necessary experimental tools, Biomaterials 28 (2) (2007) 354–369. G. Mendonça, D.B.S. Mendonça, F.J.L. Aragão, L.F. Cooper, Advancing dental implant surface technology – from micron- to nanotopography, Biomaterials 29 (28) (2008) 3822–3835. M.P. Neupane, I.S. Park, T.S. Bae, M.H. Lee, Sonochemical assisted synthesis of nano-structured titanium oxide by anodic oxidation, J. Alloy. Compd. 581 (2013) 418–422. S.D. Puckett, P.P. Lee, D.M. Ciombor, R.K. Aaron, T.J. Webster, Nanotextured titanium surfaces for enhancing skin growth on transcutaneous osseointegrated devices, Acta Biomater. 6 (6) (2010) 2352–2362. T. Sjostrom, M.J. Dalby, A. Hart, R. Tare, R.O.C. Oreffo, B. Su, Fabrication of pillarlike titania nanostructures on titanium and their interactions with human skeletal stem cells, Acta Biomater. 5 (5) (2009) 1433–1441. F. Vetrone, F. Variola, P.T. de Oliveira, S.F. Zalzal, J.-H. Yi, J. Sam, K.F. Bombonato-Prado, A. Sarkissian, D.F. Perepichka, J.D. Wuest, et al., Nanoscale oxidative patterning of metallic surfaces to modulate cell activity and fate, Nano Lett. 9 (2) (2009) 659–665. V.K. Truong, R. Lapovok, Y.S. Estrin, S. Rundell, J.Y. Wang, C.J. Fluke, R.J. Crawford, E.P. Ivanova, The influence of nano-scale surface roughness on bacterial adhesion to ultrafine-grained titanium, Biomaterials 31 (13) (2010) 3674–3683. F. Rupp, R.A. Gittens, L. Scheideler, A. Marmur, B.D. Boyan, Z. Schwartz, J. GeisGerstorfer, A review on the wettability of dental implant surfaces I: theoretical and experimental aspects, Acta Biomater. 10 (7) (2014) 2894–2906.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Nano modified SLA process for titanium implants ⁎
Youneng Xie, Jiaxin Li, Z.M. Yu , Qiuping Wei
crossmark
School of Materials Science and Engineering, Central South University, Changsha 410083, PR China
A R T I C L E I N F O
A BS T RAC T
Keywords: Biomaterials Surfaces Corrosion Microstructure
Nano structures gain great prevalence in titanium implants for its enhancement on cell differentiation and gene expression. And sandblast and acid etching (SLA), which yields micro/submicron structures, is the most popular treatment to titanium implants. Aimed at adding nano structures on SLA surfaces, a combination of SLA and H2O2 etching method is proposed. Surface morphology, roughness, surface chemistry and contact angle are characterized. Typical SLA morphology accompanied with nano pits is obtained. Reactive oxygen species are also detected on this surface with remarkable wettability. This novel surface may be promising to dental implants.
1. Introduction
2. Experimental details
Sandblast and acid-etched (SLA) has become the most prevalent surface treatment to titanium implants for its micro/submicron hierarchical structures over the past several decades [1–4]. On one hand, hierarchical structures can enlarge the contact area of titanium, which favors the adhesion, proliferation and differentiation of osteoblasts. On the other hand, they can also improve the mechanical lock on implants-bone interface, thus enhancing the initial fixation of the implants [2,5]. Nano structures attract a substantial amount of attention for their resplendent performances in many aspects especially in biomedical applications [3,5–13]. Many researchers claimed that nano structures on titanium surface can promote osteogenic differentiation. Someone even put that nano structures can improve the antimicrobial properties and decontamination function of implants. Traditional methods to prepare nano structures are anodic oxidation, plasma treatment, and the like, which is either environmentally unfriendly or expensive. Traditional SLA surface impedes the differentiation of osteoblasts and the initial fixation of the implants for the lack of nano structures. Moreover, traditional SLA surface is hydrophobic, which is unfavorable to cell attachment, let alone the differentiation. So some possible measurements should be made to modify SLA process. H2O2 is a wonderful etchant to titanium, and O22− is a hydrophilic group which can also prohibit bacterial breeding. In this study, H2O2 is used to etch SLA titanium surface, aiming at compositing nano structures with SLA surface, which may be a cheap and eco-friendly method for modifying SLA process.
2.1. Corrosion process TA2 commercial titanium plate was cut into disks (Φ15 mm) and then mirror polished to Ra < 0.5 µm. Disks were sandblasted by Al2O3 (Φ250~500 µm) at a pressure of 3 atm. Blasted disks were pretreated in a mixture of HNO3 and HF and subsequently etched in a boiling mixture of H2SO4 and HCl for several minutes and finally immersed in concentrated H2O2 for 1 h. All the samples were ultrasonically cleaned in distilled water, acetone and ultrapure water 10 min three times respectively at the end of each step. Samples were finally rinsed in ultrapure water and dried in hot air. 2.2. Materials characterization Surface morphology was observed by Scanning electron microscopy (SEM, Nova NanoSEM 230). Surface roughness was calculated by surface profiler (Dektak 150 surface profiler) with each testing line of 1000 µm. Surface chemistry was detected using X-ray photoelectron spectroscopy (XPS, ESCALAB 250Xi) with Al Kα irradiation. The binding energies for each spectrum were calibrated based on the C1s spectra of 285.0 eV. Contact angle was tested by sessile drop method. 3. Results and discussion 3.1. Surface morphology Fig. 1 shows the surface morphologies of SLA and nano-modified
⁎
Corresponding author. E-mail address: [email protected] (Z.M. Yu).
http://dx.doi.org/10.1016/j.matlet.2016.08.079 Received 3 June 2016; Received in revised form 10 August 2016; Accepted 14 August 2016 Available online 15 August 2016 0167-577X/ © 2016 Published by Elsevier B.V.
Materials Letters 186 (2017) 38–41
Y. Xie et al.
Fig. 1. Surface topography of SLA (A and C) and NSLA (B and D) titanium.
Fig. 2. XPS spectra of SLA surface (y01) and NSLA surface (y02).
39
Materials Letters 186 (2017) 38–41
Y. Xie et al.
Fig. 3. Surface profiler test results of SLA and NSLA titanium surface.
Fig. 4. Water contact angle on titanium: A) SLA, B) NSLA.
524 eV disappeared after treated in H2O2, indicating that the oxide layer on NSLA surface was thicker than SLA surface, which is beyond the critical thickness of XPS. Thicker oxide layer may also be the explanation to the disappearance of S on NSLA surface.
SLA (NSLA) titanium, from which we can see that these two surfaces show typical SLA morphologies (honeycomb-like holes with diameters ranging from 1 to 5 µm), and they are nearly the same in micro scale except fuzzy and blunt edges and some fine holes on NSLA surface. But many nano pits with diameters of tens of nanometers appear on NSLA surface when it comes to nano scale. The topography of SLA titanium in this experiment resembles that of ITI implants', which may show similar cell responses. And the nano pits on NSLA surface may favor the osteogenic differentiation of cells cultured on it. Meanwhile, nano structures on titanium surfaces can promote their microbial properties [5,14].
3.3. Surface roughness Fig. 3 shows the surface profiler results of these two specimens, and no obvious differences can be seen between them. The average surface roughness is 3.39 µm and 3.35 µm for SLA and NSLA titanium, which are also nearly the same. These results mean that H2O2 only digs nano structures on SLA surface, which is in accordance with the results in Section 3.1.
3.2. Surface chemistry Fig. 2 depicts the XPS spectra of SLA and NSLA titanium surfaces, from which we can see that both these two surfaces contain Ti, C and O, while litter S vestigital is detected only on SLA surface. C1s spectra of these two samples are nearly the same, and they can be fitted by three peaks. The peak centered at 285.0 eV can be identified as C–H or C–C component on the samples. The peak set at 286.5 eV for C=O, and peak at 289 eV for O–C=O. The O1s spectrum of SLA titanium can be postulated to be TiO2, OH and H2O corresponding to the peaks centered at 530 eV, 531.5 eV and 532.5 eV, respectively. While there is another more peak centered at 533.5 eV in the O1s spectrum of NSLA titanium, which may be O22− group due to the formation of Ti(H2O2)24+ after treated in H2O2. It is reported that O22− can significantly improve antimicrobial performance and wettability of implants through providing sustainable O, which can eventually improve initial fixation of implants. Meanwhile, from the spectra of Ti2p (Supplementary 1) we can see that the peak centered at about
3.4. Surface wettability Fig. 4 shows the contact angles of water on these two samples. From Fig. 4 we can see that contact angles are about 121° and 62.8° for SLA and NSLA titanium, respectively, which indicates a much better wettability of NSLA, and this verifies the speculation in Section 3.2. Lower contact angle of NSLA surface can be ascribed to two aspects. One is that some hydrophilic groups remained after treated in H2O2, which improves the polarization of NSLA surface. The other is the capillary effects of nano pits on NSLA surface. Wettability of biomaterials determines the biological cascade of events at the biomaterial/ host interface [15]. Hydrophilic surface favors the adsorption of protein and adherence of osteoblasts, which promotes the initial fixation of implant, thus shortening the course. Traditional SLA surface is likely to become hydrophobic when stored in atmosphere. This result indicates that H2O2 treatment may be a promising method for 40
Materials Letters 186 (2017) 38–41
Y. Xie et al.
improving the wettability of SLA surface. [3]
4. Conclusion A novel surface combining traditional SLA micron morphology with nano structures was produced by adding a simple, cheap and ecofriendly procedure to traditional SLA process. SLA and NSLA show similar morphology and surface roughness. H2O2 removes the S residual on SLA surface, and increases the oxide layer thickness. Meanwhile, O22− group vestigital was also detected on NSLA surface. Moreover, H2O2 treatment turned hydrophobic SLA surface to hydrophilic surface, which may greatly enhance the biomedical performance in a cascade of aspects. This novel surface is very promising in implant application. And this method is of great significance to traditional SLA modification.
[4]
[5]
[6]
[7]
[8] [9]
Acknowledgment [10]
We gratefully acknowledge the National Natural Foundation of China (No. 51301211) for financial support.
Science [11]
Appendix A. Supporting information [12]
Supplementary data associated with this article can be found in the online version at doi:10.1016/j.matlet.2016.08.079.
[13]
References [14] [1] R.A. Gittens, R. Olivares-Navarrete, A. Cheng, D.M. Anderson, T. McLachlan, I. Stephan, J. Geis-Gerstorfer, K.H. Sandhage, A.G. Fedorov, F. Rupp, et al., The roles of titanium surface micro/nanotopography and wettability on the differential response of human osteoblast lineage cells, Acta Biomater. 9 (4) (2013) 6268–6277. [2] Z. Qu, X. Rausch-Fan, M. Wieland, M. Matejka, A. Schedle, The initial attachment
[15]
41
and subsequent behavior regulation of osteoblasts by dental implant surface modification, J. Biomed. Mater. Res. Part A 82A (3) (2007) 658–668. Q.-L. Ma, L.-Z. Zhao, R.-R. Liu, B.-Q. Jin, W. Song, Y. Wang, Y.-S. Zhang, L.H. Chen, Y.-M. Zhang, Improved implant osseointegration of a nanostructured titanium surface via mediation of macrophage polarization, Biomaterials 35 (37) (2014) 9853–9867. B.S. Kopf, A. Schipanski, M. Rottmar, S. Berner, K. Maniura-Weber, Enhanced differentiation of human osteoblasts on Ti surfaces pre-treated with human whole blood, Acta Biomater. 19 (2015) 180–190. Y. Shibata, Y. Tanimoto, A review of improved fixation methods for dental implants. Part I: Surface optimization for rapid osseointegration, J. Prosthodont. Res. 59 (1) (2015) 20–33. O. Akhavan, E. Ghaderi, Self-accumulated Ag nanoparticles on mesoporous TiO2 thin film with high bactericidal activities, Surf. Coat. Technol. 204 (21–22) (2010) 3676–3683. E.-J. Lee, J.-S. Kwon, S.-H. Uhm, D.-H. Song, Y.H. Kim, E.H. Choi, K.-N. Kim, The effects of non-thermal atmospheric pressure plasma jet on cellular activity at SLAtreated titanium surfaces, Curr. Appl. Phys. 13 (Suppl. 1) (2013) S36–S41. H. Liu, T.J. Webster, Nanomedicine for implants: a review of studies and necessary experimental tools, Biomaterials 28 (2) (2007) 354–369. G. Mendonça, D.B.S. Mendonça, F.J.L. Aragão, L.F. Cooper, Advancing dental implant surface technology – from micron- to nanotopography, Biomaterials 29 (28) (2008) 3822–3835. M.P. Neupane, I.S. Park, T.S. Bae, M.H. Lee, Sonochemical assisted synthesis of nano-structured titanium oxide by anodic oxidation, J. Alloy. Compd. 581 (2013) 418–422. S.D. Puckett, P.P. Lee, D.M. Ciombor, R.K. Aaron, T.J. Webster, Nanotextured titanium surfaces for enhancing skin growth on transcutaneous osseointegrated devices, Acta Biomater. 6 (6) (2010) 2352–2362. T. Sjostrom, M.J. Dalby, A. Hart, R. Tare, R.O.C. Oreffo, B. Su, Fabrication of pillarlike titania nanostructures on titanium and their interactions with human skeletal stem cells, Acta Biomater. 5 (5) (2009) 1433–1441. F. Vetrone, F. Variola, P.T. de Oliveira, S.F. Zalzal, J.-H. Yi, J. Sam, K.F. Bombonato-Prado, A. Sarkissian, D.F. Perepichka, J.D. Wuest, et al., Nanoscale oxidative patterning of metallic surfaces to modulate cell activity and fate, Nano Lett. 9 (2) (2009) 659–665. V.K. Truong, R. Lapovok, Y.S. Estrin, S. Rundell, J.Y. Wang, C.J. Fluke, R.J. Crawford, E.P. Ivanova, The influence of nano-scale surface roughness on bacterial adhesion to ultrafine-grained titanium, Biomaterials 31 (13) (2010) 3674–3683. F. Rupp, R.A. Gittens, L. Scheideler, A. Marmur, B.D. Boyan, Z. Schwartz, J. GeisGerstorfer, A review on the wettability of dental implant surfaces I: theoretical and experimental aspects, Acta Biomater. 10 (7) (2014) 2894–2906.