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Preparation and characterization of α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold from Parapenaeus longirostris
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 3 (2016) 2590–2598 www.elsevier.com/locate/procedia
6th International conference on Advanced Nano Materials
Preparation and characterization of α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold from Parapenaeus longirostris El Montassir Dahmane a*, Moha Taourirte a, Nadia Eladlani a and Mohammed Rhazi b a
Laboratoire de chimie Bio organique et Macromoléculaire (LCBM) ; Département des Sciences Chimiques, Faculté des Sciences et Techniques Guéliz (FSTG), B.P. 549, Marrakech, 40000, Morocco.
b
Equipe des Macromolécules Naturelles (LMN), Ecole Normale supérieure, BP S41, Marrakech, 40000, Morocco
Abstract The α-chitin whiskers were prepared by acid hydrolysis of α-chitin from Parapenaeus longirostris shells from Moroccan local sources. A chitosan nanoscaffold in the form of a colloidal solution was obtained from the deacetylation of α-chitin whiskers under alkaline conditions. Chitosan-based nanoparticles were prepared through ionic cross-linking and gelation of chitosan by tripolyphosphate. The chemical structure and physicochemical properties of α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The length of the as-prepared whiskers ranged between 90 and 620 nm, while the width ranged between 9 and 63 nm, with the average values being about 354 and 25 nm, respectively. The obtained chitosan nanoparticles were consistently spherical with an overall diameter of approximately 32 nm. Chitosan nanoscaffold possessed an interconnected pore network with an average pore size of 200 nm. © 2014 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the Conference Committee of 6th International Conference on Advanced Nano Materials. Keywords: α-chitin whiskers, chitosan nanoparticles, chitosan nanoscaffold, Parapenaeus longirostris.
* Corresponding author: Tél. 00 212 5 24 43 46 88, fax: 00 212 5 24 43 31 70 E-mail address: [email protected], [email protected]
2214-7853 © 2014 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the Conference Committee of 6th International Conference on Advanced Nano Materials.
El Montassir Dahmane et al. / Materials Today: Proceedings 3 (2016) 2590–2598
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1. Introduction: Nanomaterials differ significantly from other materials due to the following two major principal factors: the increased surface area and quantum effects. These factors can enhance properties such as reactivity, strength, electrical characteristics and in vivo behaviour [1]. As a particle decreases in size, a greater proportion of atoms are found at the surface compared to those inside. For example, a particle of size 30 nm has 5% of its atoms on its surface, at 10 nm 20% of its atoms, and at 3 nm 50% of its atoms. Thus nanoparticles have a much greater surface area per unit mass compared with larger particles. As growth and catalytic chemical reactions occur at surfaces, this means that a given mass of material in nanoparticulate form will be much more reactive than the same mass of material made up of larger particles. The biocompatibility and biodegradability of inorganic nanomaterials are much more limited than those of naturally organic ones [2]. In nature, a large number of animals and plants synthesize extracellular high-performance skeletal biocomposites that consist of a matrix reinforced by fibrous biopolymers [3]. Chitin (one of a classical example), a naturally abundant polymer consists of 2-acetamido 2-deoxy-ß-D-glucose through a ß(1-4) linkage. In spite of the presence of nitrogen, it may be regarded as cellulose with hydroxyl at position C-2 replaced by an acetamido group. Chitin and its derivatives, mainly chitosan (obtained after deacetylation of chitin), have attracted the interest of many researchers and industries owning to its physical– chemical properties. These polymers display antimicrobial activity, biocompatibility, biodegradability and non-toxic properties. These properties clearly point out that chitin and chitosan have greater potential for future development in different fields of science namely drug delivery, gene delivery, cell imaging, sensors and also in the treatment as well as diagnosis of some diseases like cancer [4]. Chitosan and chitin based nanomaterials have superior physical and chemical properties such as high surface area, porosity, tensile strength, conductivity, photo-luminescent as well as increased mechanical properties as comparison to pure chitin and chitosan [5]. Since there have not been prior reports on the preparation of nanomaterials from Parapenaeus longirostris shells, α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold were then prepared from shells of Parapenaeus longirostris. 2. Methods. 2. 1. Preparation of chitin and chitosan The extraction and characterization of chitin and chitosan from Parapenaeus longirostris from Moroccan local sources are detailed in our previous article [6]. The obtained chitin has a high acetylation percent (93%) and the corresponding chitosan has a medium molecular weight (M= 71 Kg/mol) with low acetylation percent (10%) [6]. 2.2. Preparation of α-chitin whiskers α-chitin whiskers were prepared by acid hydrolysis of α-chitin from shells of Parapenaeus longirostris shrimps. αchitin (1g) was hydrolyzed with 3 N HCl (300 ml) at 105 °C for 3 h under vigorous stirring. After acid hydrolysis, the suspensions were diluted with deionised water, followed by centrifugation at 5000 rpm for 30 min. This process was repeated three times. Finally, the product was washed with deionised water until neutral to obtain chitin whiskers. 2. 3. Preparation of chitosan nanoscaffold. The deacetylation reaction of α-chitin whiskers was made using NaOH. α-chitin whiskers in aqueous solution (20 ml, 2 g) was stirred in 100ml of aqueous NaOH (50% w/v) for 7 h at 150°C. In 2001, Kurita has indicated that deacetylation of chitin can be highly facilitated by steeping in strong sodium hydroxide at room temperature before heating. We adapted this method of steeping for our samples for one 1h before conversion by heat [7]. The resulting chitosan nanoscaffold was washed with distilled water until neutral, freeze-dried, and stored at 4°C until further use.
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2. 4. Preparation of chitosan nanoparticles. Chitosan nanoparticles were prepared by ionic gelation of chitosan with tripolyphosphate (TPP) anions. chitosan solution (2.5 mg/ml) was prepared by dissolving it in 0.3 M aqueous acetic acid (6 ml). Then 6.25 ml of chitosan solution was added drop wise and under continuous stirring to 2.5 ml of TPP aqueous solution having a concentration of 2.5mg/ml. An opalescent suspension was formed instantaneously. Nanoparticles were then separated by centrifugation at 5,000 rpm at 20°C for 30 minutes, freeze-dried, and stored at 4°C until further use. 2. 5. Transmission Electron Microscope (TEM) Analyses. Samples of nanomaterials were prepared from a drop of a dilute nanoparticles suspension in water, which was deposited on a carbon coated copper grid. Excess solution was removed with a filter paper, and let dry by natural evaporation. The sample grid was observed at 120 kV using a Tecnai G2 transmission electron microscope. 2. 6. Fourier Transform Infrared Spectroscopy (FTIR) analyses. FTIR spectra were recorded on a Fourier Transform Infrared Spectrometer (Bruker VERTEX- 70) using KBr pellets. Spectra (32 scans at 4 cm-1 resolution) were collected in the 4000-400 cm-1 range. 2. 7. X-ray powder diffractometry (XRD) X-ray diffraction analysis was applied to detect the crystallinity of the prepared nanomaterials samples of using a X Philips X'Pert (θ-θ) X-ray diffractometer with CuKα radiation (λ=1.54 Å). The 2θ angle was scanned between 5° and 70° (4.8°/min). The voltage was 40 kV and the intensity 30 mA. 3. Results and discussion. 3. 1. α-chitin whiskers 3. 1. 1. morphology and size. TEM image of a dilute suspension of α-chitin whiskers from acid hydrolysis of Parapenaeus longirostris shells is represented in figure 1. Such a suspension exhibited a colloidal behaviour due to the presence of the positive charge on chitin whiskers. The shrimp chitin used to prepare α-chitin whiskers in this work had a degree of acetylation of 93%. The presence of some protonated amino groups (–NH3+) on the whisker surface was sufficient enough to stabilize the colloidal behavior of the α-chitin whiskers suspension [8]. The length of the chitin fragments ranged from 90 to 620 nm, while the width ranged from 9 to 63 nm. The average length (L) and width (d) of these whiskers were about 354 and 25 nm, respectively, and the average aspect ratio (L/d) was of 14 (figure 2). These dimensions are in the range of the previously reported values for chitin whiskers obtained from chitin extracted from Penaeus merguiensis shells (L = 80 to 820 nm and d = 8 to 74 nm) [9]. 3. 1. 2. Crystalline structure. Figure 3 shows the crystalline morphology of whiskers and chitin. The major peaks at 9° and 19° (2θ) of whiskers are significantly sharp as compared to the starting chitin, confirmed the crystalline structure of whiskers.
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Figure 1. Transmission electron micrograph of a dilute suspension of α-chitin whiskers from Parapenaeus longirostris shells.
Figure 2. Histograms showing the length and width distribution of prepared α-chitin whiskers.
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Figure 3. Wide-angle X-ray diffraction patterns of pure chitin and α-chitin whiskers
Figure 4: FTIR spectra of chitin and whiskers
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3. 1. 3. Fourier Transform Infrared Spectroscopy. Spectra of chitin and whiskers are shown in Figure 4. Chitin and whiskers presented the same characteristic peaks: at 3400 cm–1 attributed to the –NH2 and – OH groups stretching vibration and intermolecular hydrogen bonding. The two bands at 1659 and 1624 cm-1 correspond to the stretching of amide I, the band at 1659 cm-1 is assigned to stretching of the C=O group hydrogen bonded to N–H of the neighboring intra-sheet chain, regarding the 1624 cm-1 band, its occurrence may indicate a specific hydrogen bond of C=O with the hydroxyl-methyl group of the next chitin residue of the same chain [10]. The absorption band at 1556 cm-1 and 1315 cm-1 corresponds to amide II (N-H bending) and amide III (C-N stretching) respectively [11]. 3. 2. Chitosan nanoscaffold 3. 2. 1. Morphology. A colloidal solution was obtained from the deacetylation of whiskers. TEM micrograph of this solution reveals the nanoscaffold fibrous network morphology. The fibrous network forms a porous structure with the pore diameter of about 200 nm (figure 5). 3. 2. 2. Fourier Transform Infrared Spectroscopy. After deacetylation of whiskers the peak at 1556 cm–1 disappeared along with the appearance of a new sharp peak at 1595 cm–1 (NH2 bending) (figure 6). 3. 3. Chitosan nanoparticles. 3. 3. 1. Morphology. The nanoparticles were regularly spherical displaying smooth surfaces with an average diameter of 32 nm (figure 7). 3. 3. 2. Fourier Transform Infrared Spectroscopy. The resulting nanoparticles were also examined by FTIR (figure 8), mainly to confirm the occurrence of crosslinking. The spectrum of chitsan and TPP is also given as reference. The chitosan matrix presented some characteristic peaks: at 3400 cm–1 attributed to the –NH2 and – OH groups stretching vibration and intermolecular hydrogen bonding; at 1598 cm–1 and 1640 cm–1 ascribed to the N-H bending and primary amide groups, respectively. After crosslinking with TPP, the peak at 1598 cm–1 shifted to 1535 cm–1 and the peak at 1640 cm–1 disappeared along with the appearance of a new sharp peak at 1631 cm–1. These differences are related to the association between phosphate and ammonium ions, attesting the success of ionic- crosslinking [12].
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Figure 5: Transmission electron micrograph of chitosan nanoscaffold from Parapenaeus longirostris shells.
Figure 6: FTIR spectra of whiskers and chitosan nanoscaffold
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Figure 7: Transmission electron micrograph of a dilute suspension of chitosan nanoparticles from Parapenaeus longirostris shells.
Figure 8: FTIR spectra of TPP, chitosan matrix and chitosan nanoparticles
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4. Conclusions. α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold were successfully prepared from chitin and chitosan from Parapenaeus longirostris shells. Chitosan and chitin are known as biomaterials due to its biocompatibility, biodegradability, and non-toxic properties. These properties clearly point out that the obtained nanomaterials (α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold) have greater potential for future development in different fields especially in the biomedical field. References: [1] D. Divya, Int. J. Drug Dev. & Res., 2011, 3(4): 4-8 [2] G. Schmidt, & M. M. Malwitz, Curr. Opin. Colloid Interface Sci., 2003, 8, 103. [3] A. C. Neville, Biology of fibrous composites: Development beyond the cell membrane., Cambridge: Cambridge University Press., (1993). [4] E.M. Dahmane, M. Rhazi, and M. Taourirte, Bull. Korean Chem. Soc., 2013, 345 1333. [5] K. S. Sudheesh, K. M. Ajay, A. A. Omotayo, B. M. Bhekie, Int. J. Biol. Macromol., 2013, 59 46– 58 [6] E.M. Dahmane, M. Taourirte, N. Eladlani, M. Rhazi., Int J Polym Anal Ch., 2014, 19: 342–351 [7] K. Kurita, Prog. Polym. Sci., 2001. 26, 1921–1971. [8] J.F. Rovel, R.H. Marchessaultf, Int J Biol Macromol 1993, 15: 329–35 [9] P. Wongpanit, N. Sanchavanakit, P. Pavasant, T. Bunaprasert, Y. Tabata, R. Rujiravanit, Eur Polym J., 2007, 43 4123–4135 [10] B. Focher, A. Naggi, G. Torri, A. Cosani, M. Terbojevich. Carbohydr Polym 1992, 17:97–102. [11] C. Qin, H. Li, Q. Xiao, Y. Liu, J. Zhu, & Y. Du, Carbohydrate Polymers, (2006). 63(3), 367–374. [12] J.Z. Knaul, S.M. Hudson, K.A.M. Creber, J Appl Polym Sci., 1999, 72, 1721.
ScienceDirect Materials Today: Proceedings 3 (2016) 2590–2598 www.elsevier.com/locate/procedia
6th International conference on Advanced Nano Materials
Preparation and characterization of α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold from Parapenaeus longirostris El Montassir Dahmane a*, Moha Taourirte a, Nadia Eladlani a and Mohammed Rhazi b a
Laboratoire de chimie Bio organique et Macromoléculaire (LCBM) ; Département des Sciences Chimiques, Faculté des Sciences et Techniques Guéliz (FSTG), B.P. 549, Marrakech, 40000, Morocco.
b
Equipe des Macromolécules Naturelles (LMN), Ecole Normale supérieure, BP S41, Marrakech, 40000, Morocco
Abstract The α-chitin whiskers were prepared by acid hydrolysis of α-chitin from Parapenaeus longirostris shells from Moroccan local sources. A chitosan nanoscaffold in the form of a colloidal solution was obtained from the deacetylation of α-chitin whiskers under alkaline conditions. Chitosan-based nanoparticles were prepared through ionic cross-linking and gelation of chitosan by tripolyphosphate. The chemical structure and physicochemical properties of α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The length of the as-prepared whiskers ranged between 90 and 620 nm, while the width ranged between 9 and 63 nm, with the average values being about 354 and 25 nm, respectively. The obtained chitosan nanoparticles were consistently spherical with an overall diameter of approximately 32 nm. Chitosan nanoscaffold possessed an interconnected pore network with an average pore size of 200 nm. © 2014 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the Conference Committee of 6th International Conference on Advanced Nano Materials. Keywords: α-chitin whiskers, chitosan nanoparticles, chitosan nanoscaffold, Parapenaeus longirostris.
* Corresponding author: Tél. 00 212 5 24 43 46 88, fax: 00 212 5 24 43 31 70 E-mail address: [email protected], [email protected]
2214-7853 © 2014 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the Conference Committee of 6th International Conference on Advanced Nano Materials.
El Montassir Dahmane et al. / Materials Today: Proceedings 3 (2016) 2590–2598
2591
1. Introduction: Nanomaterials differ significantly from other materials due to the following two major principal factors: the increased surface area and quantum effects. These factors can enhance properties such as reactivity, strength, electrical characteristics and in vivo behaviour [1]. As a particle decreases in size, a greater proportion of atoms are found at the surface compared to those inside. For example, a particle of size 30 nm has 5% of its atoms on its surface, at 10 nm 20% of its atoms, and at 3 nm 50% of its atoms. Thus nanoparticles have a much greater surface area per unit mass compared with larger particles. As growth and catalytic chemical reactions occur at surfaces, this means that a given mass of material in nanoparticulate form will be much more reactive than the same mass of material made up of larger particles. The biocompatibility and biodegradability of inorganic nanomaterials are much more limited than those of naturally organic ones [2]. In nature, a large number of animals and plants synthesize extracellular high-performance skeletal biocomposites that consist of a matrix reinforced by fibrous biopolymers [3]. Chitin (one of a classical example), a naturally abundant polymer consists of 2-acetamido 2-deoxy-ß-D-glucose through a ß(1-4) linkage. In spite of the presence of nitrogen, it may be regarded as cellulose with hydroxyl at position C-2 replaced by an acetamido group. Chitin and its derivatives, mainly chitosan (obtained after deacetylation of chitin), have attracted the interest of many researchers and industries owning to its physical– chemical properties. These polymers display antimicrobial activity, biocompatibility, biodegradability and non-toxic properties. These properties clearly point out that chitin and chitosan have greater potential for future development in different fields of science namely drug delivery, gene delivery, cell imaging, sensors and also in the treatment as well as diagnosis of some diseases like cancer [4]. Chitosan and chitin based nanomaterials have superior physical and chemical properties such as high surface area, porosity, tensile strength, conductivity, photo-luminescent as well as increased mechanical properties as comparison to pure chitin and chitosan [5]. Since there have not been prior reports on the preparation of nanomaterials from Parapenaeus longirostris shells, α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold were then prepared from shells of Parapenaeus longirostris. 2. Methods. 2. 1. Preparation of chitin and chitosan The extraction and characterization of chitin and chitosan from Parapenaeus longirostris from Moroccan local sources are detailed in our previous article [6]. The obtained chitin has a high acetylation percent (93%) and the corresponding chitosan has a medium molecular weight (M= 71 Kg/mol) with low acetylation percent (10%) [6]. 2.2. Preparation of α-chitin whiskers α-chitin whiskers were prepared by acid hydrolysis of α-chitin from shells of Parapenaeus longirostris shrimps. αchitin (1g) was hydrolyzed with 3 N HCl (300 ml) at 105 °C for 3 h under vigorous stirring. After acid hydrolysis, the suspensions were diluted with deionised water, followed by centrifugation at 5000 rpm for 30 min. This process was repeated three times. Finally, the product was washed with deionised water until neutral to obtain chitin whiskers. 2. 3. Preparation of chitosan nanoscaffold. The deacetylation reaction of α-chitin whiskers was made using NaOH. α-chitin whiskers in aqueous solution (20 ml, 2 g) was stirred in 100ml of aqueous NaOH (50% w/v) for 7 h at 150°C. In 2001, Kurita has indicated that deacetylation of chitin can be highly facilitated by steeping in strong sodium hydroxide at room temperature before heating. We adapted this method of steeping for our samples for one 1h before conversion by heat [7]. The resulting chitosan nanoscaffold was washed with distilled water until neutral, freeze-dried, and stored at 4°C until further use.
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2. 4. Preparation of chitosan nanoparticles. Chitosan nanoparticles were prepared by ionic gelation of chitosan with tripolyphosphate (TPP) anions. chitosan solution (2.5 mg/ml) was prepared by dissolving it in 0.3 M aqueous acetic acid (6 ml). Then 6.25 ml of chitosan solution was added drop wise and under continuous stirring to 2.5 ml of TPP aqueous solution having a concentration of 2.5mg/ml. An opalescent suspension was formed instantaneously. Nanoparticles were then separated by centrifugation at 5,000 rpm at 20°C for 30 minutes, freeze-dried, and stored at 4°C until further use. 2. 5. Transmission Electron Microscope (TEM) Analyses. Samples of nanomaterials were prepared from a drop of a dilute nanoparticles suspension in water, which was deposited on a carbon coated copper grid. Excess solution was removed with a filter paper, and let dry by natural evaporation. The sample grid was observed at 120 kV using a Tecnai G2 transmission electron microscope. 2. 6. Fourier Transform Infrared Spectroscopy (FTIR) analyses. FTIR spectra were recorded on a Fourier Transform Infrared Spectrometer (Bruker VERTEX- 70) using KBr pellets. Spectra (32 scans at 4 cm-1 resolution) were collected in the 4000-400 cm-1 range. 2. 7. X-ray powder diffractometry (XRD) X-ray diffraction analysis was applied to detect the crystallinity of the prepared nanomaterials samples of using a X Philips X'Pert (θ-θ) X-ray diffractometer with CuKα radiation (λ=1.54 Å). The 2θ angle was scanned between 5° and 70° (4.8°/min). The voltage was 40 kV and the intensity 30 mA. 3. Results and discussion. 3. 1. α-chitin whiskers 3. 1. 1. morphology and size. TEM image of a dilute suspension of α-chitin whiskers from acid hydrolysis of Parapenaeus longirostris shells is represented in figure 1. Such a suspension exhibited a colloidal behaviour due to the presence of the positive charge on chitin whiskers. The shrimp chitin used to prepare α-chitin whiskers in this work had a degree of acetylation of 93%. The presence of some protonated amino groups (–NH3+) on the whisker surface was sufficient enough to stabilize the colloidal behavior of the α-chitin whiskers suspension [8]. The length of the chitin fragments ranged from 90 to 620 nm, while the width ranged from 9 to 63 nm. The average length (L) and width (d) of these whiskers were about 354 and 25 nm, respectively, and the average aspect ratio (L/d) was of 14 (figure 2). These dimensions are in the range of the previously reported values for chitin whiskers obtained from chitin extracted from Penaeus merguiensis shells (L = 80 to 820 nm and d = 8 to 74 nm) [9]. 3. 1. 2. Crystalline structure. Figure 3 shows the crystalline morphology of whiskers and chitin. The major peaks at 9° and 19° (2θ) of whiskers are significantly sharp as compared to the starting chitin, confirmed the crystalline structure of whiskers.
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Figure 1. Transmission electron micrograph of a dilute suspension of α-chitin whiskers from Parapenaeus longirostris shells.
Figure 2. Histograms showing the length and width distribution of prepared α-chitin whiskers.
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Figure 3. Wide-angle X-ray diffraction patterns of pure chitin and α-chitin whiskers
Figure 4: FTIR spectra of chitin and whiskers
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3. 1. 3. Fourier Transform Infrared Spectroscopy. Spectra of chitin and whiskers are shown in Figure 4. Chitin and whiskers presented the same characteristic peaks: at 3400 cm–1 attributed to the –NH2 and – OH groups stretching vibration and intermolecular hydrogen bonding. The two bands at 1659 and 1624 cm-1 correspond to the stretching of amide I, the band at 1659 cm-1 is assigned to stretching of the C=O group hydrogen bonded to N–H of the neighboring intra-sheet chain, regarding the 1624 cm-1 band, its occurrence may indicate a specific hydrogen bond of C=O with the hydroxyl-methyl group of the next chitin residue of the same chain [10]. The absorption band at 1556 cm-1 and 1315 cm-1 corresponds to amide II (N-H bending) and amide III (C-N stretching) respectively [11]. 3. 2. Chitosan nanoscaffold 3. 2. 1. Morphology. A colloidal solution was obtained from the deacetylation of whiskers. TEM micrograph of this solution reveals the nanoscaffold fibrous network morphology. The fibrous network forms a porous structure with the pore diameter of about 200 nm (figure 5). 3. 2. 2. Fourier Transform Infrared Spectroscopy. After deacetylation of whiskers the peak at 1556 cm–1 disappeared along with the appearance of a new sharp peak at 1595 cm–1 (NH2 bending) (figure 6). 3. 3. Chitosan nanoparticles. 3. 3. 1. Morphology. The nanoparticles were regularly spherical displaying smooth surfaces with an average diameter of 32 nm (figure 7). 3. 3. 2. Fourier Transform Infrared Spectroscopy. The resulting nanoparticles were also examined by FTIR (figure 8), mainly to confirm the occurrence of crosslinking. The spectrum of chitsan and TPP is also given as reference. The chitosan matrix presented some characteristic peaks: at 3400 cm–1 attributed to the –NH2 and – OH groups stretching vibration and intermolecular hydrogen bonding; at 1598 cm–1 and 1640 cm–1 ascribed to the N-H bending and primary amide groups, respectively. After crosslinking with TPP, the peak at 1598 cm–1 shifted to 1535 cm–1 and the peak at 1640 cm–1 disappeared along with the appearance of a new sharp peak at 1631 cm–1. These differences are related to the association between phosphate and ammonium ions, attesting the success of ionic- crosslinking [12].
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Figure 5: Transmission electron micrograph of chitosan nanoscaffold from Parapenaeus longirostris shells.
Figure 6: FTIR spectra of whiskers and chitosan nanoscaffold
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Figure 7: Transmission electron micrograph of a dilute suspension of chitosan nanoparticles from Parapenaeus longirostris shells.
Figure 8: FTIR spectra of TPP, chitosan matrix and chitosan nanoparticles
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4. Conclusions. α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold were successfully prepared from chitin and chitosan from Parapenaeus longirostris shells. Chitosan and chitin are known as biomaterials due to its biocompatibility, biodegradability, and non-toxic properties. These properties clearly point out that the obtained nanomaterials (α-chitin whiskers, chitosan nanoparticles and chitosan nanoscaffold) have greater potential for future development in different fields especially in the biomedical field. References: [1] D. Divya, Int. J. Drug Dev. & Res., 2011, 3(4): 4-8 [2] G. Schmidt, & M. M. Malwitz, Curr. Opin. Colloid Interface Sci., 2003, 8, 103. [3] A. C. Neville, Biology of fibrous composites: Development beyond the cell membrane., Cambridge: Cambridge University Press., (1993). [4] E.M. Dahmane, M. Rhazi, and M. Taourirte, Bull. Korean Chem. Soc., 2013, 345 1333. [5] K. S. Sudheesh, K. M. Ajay, A. A. Omotayo, B. M. Bhekie, Int. J. Biol. Macromol., 2013, 59 46– 58 [6] E.M. Dahmane, M. Taourirte, N. Eladlani, M. Rhazi., Int J Polym Anal Ch., 2014, 19: 342–351 [7] K. Kurita, Prog. Polym. Sci., 2001. 26, 1921–1971. [8] J.F. Rovel, R.H. Marchessaultf, Int J Biol Macromol 1993, 15: 329–35 [9] P. Wongpanit, N. Sanchavanakit, P. Pavasant, T. Bunaprasert, Y. Tabata, R. Rujiravanit, Eur Polym J., 2007, 43 4123–4135 [10] B. Focher, A. Naggi, G. Torri, A. Cosani, M. Terbojevich. Carbohydr Polym 1992, 17:97–102. [11] C. Qin, H. Li, Q. Xiao, Y. Liu, J. Zhu, & Y. Du, Carbohydrate Polymers, (2006). 63(3), 367–374. [12] J.Z. Knaul, S.M. Hudson, K.A.M. Creber, J Appl Polym Sci., 1999, 72, 1721.