Compatibility study of alginate/keratin blend for biopolymer development
Abstract
The ultimate characteristics of blend film depend on the properties of its polymeric components, composition, and on the compatibility of the polymers. Binary polymer blend films of alginate (ALG) and keratin (KER) fibers (obtained from chicken feathers) were prepared by simple solution casting techniques and their compatibility properties were studied by X-ray diffraction and scanning electron microscopy. The tensile strength and percent of elongation were measured by a tensile strength tester. The results of the present studies elucidate that ALG and KER are compatible and suitable for the development of a blend film. It was found that the ALG/KER blend ratios of 90:10 and 80:20 possess characteristics to make a blend film with a high tensile strength value. The blend with composition 90:10 of ALG/KER is the one of the strongest candidates in the preparation of blending films, because it has the highest tensile strength (0.38 MPa) and percentage of elongation (59.5%) among all tested blend compositions. The blend ratio of 80:20 of ALG/KER achieves maximum compatibility, since its intensity pattern changes drastically as recorded in an X-ray diffraction study. The fabricated blend film can be a suitable candidate for a range of biomaterials such as for a drug delivery vesicle, hydrogel, and scaffolding, etc.
J Appl Biomater Funct Mater 2015; 13(4): e332 - e339
Article Type: ORIGINAL RESEARCH ARTICLE
DOI:10.5301/jabfm.5000242
Authors
Pratima Gupta, Kush Kumar Nayak
Article History
• Accepted on 25/04/2015
• Available online on 08/09/2015
• Published online on 18/12/2015
Disclosures
Financial support: The authors declare that the present work has been done without any financial support.
Conflict of interest: The authors declare they have no conflict of interest.
Biopolymers are considered a versatile material and their properties depend upon the molecular mass, structure, and degree of interactions. The preparation of new biopolymers with the required specifications is a difficult and time-consuming process. To overcome this problem, an alternative process is available known as biopolymer blending technology, however, this technique requires detailed information about the interactions and miscibility of biopolymers with each other (1). The degree of compatibility is a significant characteristic to develop a blend and it also helps to achieve the required mechanical strength of a blend material (2). For these reasons, miscible biopolymer blends are receiving more attention as biomaterial applications. The intention of the present study is thus to observe the miscibility property of alginate (ALG) and keratin (KER) polymers with respect to their concentration in the blend to fabricate an ALG/KER blend film.
ALG is a naturally occurring anionic polysaccharide, a linear copolymer with homopolymeric blocks of (1-2-3-4)-linked β-D-mannuronate (M) and its C-5 epimer α-L-guluronate (G) residues, respectively and covalently linked together in different sequences or blocks (3). ALG is distributed widely in the cell walls of brown algae (4) and is extensively investigated for numerous biomedical applications (5) because of its low toxicity (6), biocompatibility (7), mild gelation by the addition of divalent cations (8), and due to its relatively low cost. It is reported that ALG is readily used for preparation of scaffolding materials such as microcapsules, sponges, microspheres, hydrogels, fibers, and foams (9).
KER belongs to the family of fibrous structural proteins (10). KER contains a high percentage of cystine in its solid state, which helps to form macroscopic structures. It is well known that keratin has a unique molecular structure and a crystal arrangement as well as a high degree of order in the arrangement of the polypeptide chains (11). KER is a good biomaterial that is used in tissue engineering due to its biocompatibility and biodegradability, even accelerating the growth of fibroblasts (12, 13).
Blend materials made from a combination of 2 or more polymers have traditionally been designed to interact with biological systems. Blend materials derived from natural sources have a long history in the fields of tissue engineering, scaffold fabrication, and in drug delivery (13-14-15-16-17-18). Plenty of attention has been focused in the past on the electrospinning of various protein polymers such as fibrinogen (19), gelatin (20), silk fibroin (21), collagen (22), and elastin (23). Nevertheless, scarse attention has been given to keratin even though it is one of the most abundant proteins in the form of feathers, hair, nails, wool, and horns (13). Regenerated keratin possesses poor mechanical properties, which confine its practical implementation as described by Rouse and Van Dyke (24). However, this limitation can be overcome by blending keratin with natural and/or synthetic polymers having better structural and mechanical properties. There are a number of reported works available that give an explanation about keratin and its blend with natural and synthetic polymer to obtain value-added products (25-26-27-28-29). In a previous review article, a useful discussion has been provided by the authors on the role and depiction of protein-based biopolymers (30).
The concept behind the development of ALG/KER blend film was to produce derivatives having combined properties of both polymers in terms of functions, structures, and applications. ALG and KER both are well-known biomaterials and their blend can offer a system that allows altered properties of both polymers to persist, such as mechanical strength, gelation rate, biodegradability, water retention capacity, flexibility, cell affinity, etc. The application of the proposed blend can vary as per its final characteristics: 1) it can be used as laminating film to maintain the moisture of fruits and vegetable; 2) for the fabrication of porous scaffold from ALG/KER for tissue engineering; and 3) as hydrogel for a drug delivery system. However, this kind of blend system can also be used for the immobilization of specific ligands such as peptide and sugar fragments via the crosslinking method. Apart from the fact that the ALG/KER blend system can be used for a range of applications from micro to macro levels depends on the final characteristics of the blend products as described in the authors’ previous review article (30).
In the present article, the compatibility of ALG and KER was studied along with the development of ALG/KER blend film and its characterization. These polymers are usually of lower density than inorganic ones, relatively easy to obtain, and environmentally friendly (26). As of today, there are no articles or citations available explaining the degree of compatibility between ALG and KER polymers or on their blend film properties. The results of this study suggest that these 2 polymers have a good ability to mix with each other and can be used to form a blend film with high enough tensile strength.
Materials and methods
Materials
The polymers used were ALG (sodium salt form) 91% food-grade, purchased from LOBA Chemie (Mumbai, India) and KER isolated in a laboratory from chicken feathers collected from the local market of Raipur, Chhattisgarh, India. All other reagents that were used are commercially available: glycerol (mol. wt. 92.09) from Himedia (Mumbai, India), calcium chloride (mol. wt. 147.02) and 2-mercatpoethanol (mol. wt. 78.13) from LOBA Chemie, sodium dodecyl sulfate (SDS) (mol. wt. 288.38) and urea (mol. wt. 60.06) was purchased from Merck (Whitehouse Station, NJ, USA).
Preparation of ALG/KER blend films
The stock solution of ALG 3.33% (w/v) was prepared and homogenized by mixing it with the help of a magnetic stirrer at 50°C for 8 h. The stock solution was then stored at room temperature. The homogenized solution of ALG becomes more viscous above the concentration 3.33% and more diluted below 3.33%, which causes problems in fabricating the blend film. Feather KER was extracted according to the method described by Yamauchi et al (31). A KER stock solution 7.6% (w/v) was then homogenized by a magnetic stirrer at 60°C for 10 h and kept for 7 days at room temperature, subsequently filtered through stainless steel mesh for the removal of sediments and large particles. The obtained KER solution was then stored at room temperature for film formation. The KER concentration was kept higher than the ALG because the volume ratio of KER was applied in the blend ratio in ascending order and also to study the effect of KER in biopolymer development. The blend solutions with a final volume of 20 mL were prepared in the 5 different percentage ratios (v/v) 90:10, 80:20, 70:30, 60:40, and 50:50 of ALG/KER, respectively.
The blends of ALG/KER were prepared by adding KER solution into the ALG solution in the respective volumes as mentioned above and proper mixing was performed on a magnetic stirrer for 2 h. After that, 2% glycerol (v/v) was added to each blend composition as a plasticizer. Subsequently, blend solutions were stirred at 55°C for 3 h for proper blending, then casted in a Teflon-coated plastic box (85 × 50 × 20 mm3) and allowed to dry at ambient temperature. Later, the semitransparent films were taken out carefully from the Teflon-coated box, then the films were immersed in a 1% CaCl2 solution for 5 min. After that, they were left again at ambient temperature for drying. The purpose behind the CaCl2 treatment was to improve crosslinking of the alginate molecules, which increases the strength of the film (32).
The same procedure was applied to the fabrication of a native ALG film without the addition of KER and it was used as a control film for X-ray diffraction (XRD), scanning electron microscope (SEM), and mechanical strength analysis. The potential effect of the polymer concentration on blend film has been well discussed under the results section, including XRD, SEM, and a tensile test study.
Analytical analysis
X-ray diffraction
The X’Pert3 Powder diffractometer (PANalytical, Almelo, The Netherlands) was used for the XRD spectrum measurements at the Department of Metallurgical Engineering, National Institute of Technology Raipur, India. The film samples were kept inside the platform of an XRD chamber under an applied voltage of 40 kV and a current of 30 mA. Subsequently, the sample was scanned in the range of 5 to 40 degrees (2θ range) with the speed of 4 degrees/min.
Scanning electron microscope
The surface morphology of the ALG/KER blend films was studied by SEM (Zeiss EVO 18–Special edition, Carl Zeiss Microscopy, Oberkochen, Germany) available from the Department of Metallurgical Engineering, National Institute of Technology Raipur, India. The samples were kept on the SEM platform mounted in a vacuum chamber without any coating. The SEM images were taken at the magnification of 500X with an acceleration voltage of 3 kV.
Mechanical strength
The tensile value of blend films was determined by using digital tensile tester (KANT Plastology, Ahmedabad, India) (ASTM D 638). The maximum load capacity of the machine was 2.5 KN. The blend film was cut into rectangular pieces of 100 × 15 mm2, after which the sample was mounted on a platform of the tensile tester machine to conduct an experiment. The speed of the machine was set at the rate of 100 mm/min. The elongation length, percent of elongation, and the tensile strength were calculated.
Degradation study of the blend film
The degradation study of the blend film was conducted in phosphate buffer saline (PBS) solution at 37°C. The samples were cut into small pieces and its initial dry weight (Wi) was measured, then transferred into a container having PBS and incubated in a shaking incubator at 37°C. Subsequently, the tested samples were collected after weeks 1, 2, 3, and 4 of incubation and dried at ambient temperature. After drying was complete, the dry weight (Wt) of the blend film was measured. The percentage of weight loss of the blend film was then calculated from the following equation:
Weightloss(%)=Wi−WtWi×100 Eq. [1]
where
Wi = Dry weight of scaffold, at initial time
Wt = Dry weight of scaffold, at the time ‘t’ i.e. weeks 1, 2, 3, and 4
Water retention capacity of the blend film
The amount of water retains by the blend material give the idea about its hydrophilic characteristics. The water retention capacity of the blend film was calculated by applying the following equation:
WR=W2−W1W1×100 Eq. [2]
where
W1= dry weight, and W2 = weight of the blend film after soaked in water
Results and discussion
Compatibility study of alginate and keratin
X-ray diffraction analysis
X-ray diffraction spectrum of the native ALG film and KER powder is shown in Figure 1. The XRD pattern of native ALG and KER gives a maximum intensity at near 4100 and 7543 with 2θ near 14° and 19°, respectively, confirming the data of previous researchers (33-34-35). The broad peak of KER near at 19° represents a β-sheet structure of the protein molecule (36). The XRD spectra of KER has a slight shoulder at around 10° that points towards its crystalline properties of protein (37). The XRD spectra of blend films are illustrated in Figure 2, the intensity of native ALG and KER dropped when they blended together. The XRD spectra of ALG/KER blend film with the blend ratio 90:10, 80:20, 70:30, 60:40, and 50:50 gives the highest intensity near 3571, 1713, 5128, 7694, 3264 at an angle of 2θ, 22°, 21.8°, 6.8°, 7° and 7°, respectively. The XRD spectra of blends with all 5 tested ratios gives a new peak in between the 6°-8° angle of 2θ which is not present in the spectra of native KER and ALG. In addition, the blend spectrum intensity becomes decreased as compared to the spectra of native ALG and native KER. The formation of the new peak and decrease in the peak intensity in the blend spectrum shows that the structure of native ALG and KER become altered when they become blended into each other and form a new structural pattern in the blend. These intensity patterns and its characteristics help to identify the compatibility information of the blends (38). It is reported that if the blend systems are compatible then the intensity decrease should be non-proportional to the composition of ALG/KER and vice-versa (38-39-40).
X-ray diffraction spectrum of native ALG film and KER powder. XRD spectra of native ALG and KER give a maximum intensity at near 4100 and 7543 with 2θ near 14° and 19°, respectively.
XRD spectrum of the ALG/KER blends prepared with 5 different ratios 90:10, 80:20, 70:30, 60:40 and 50:50. The new peak was observed in the XRD spectra of blends near 6°-8° due to change in structure of native polymers. The maximum intensity of native polymers becomes shifted down when blended together.
Several works are reported in which the structural compatibility between blend components was examined by XRD. For example, the compatibility study of polyimide blends by Jou et al (38) explains how the intensity of the XRD pattern gives aids in understanding the polymer substance compatibility of a blend composition. The compatibility between carboxy-methyl-cellulose and soy-protein was investigated by Su et al (40), who report that the blends showed strong reflections at 22°. The intensity decreased significantly compared with the intensity of the pure soy-protein reflection, which is the sign of structural interaction between blend components. In similar studies, Tian et al (39) identify the interaction between soy-protein and agar. They found that the peak on native agar at 18.38° and a slight shoulder at around 14° diminished and a new weak peak at about 11.5° was observed after blended with soy-protein, which indicating the structure of the agar was changed. In ALG/KER spectrum (Fig. 2) it was observed that the intensity of all blends was decreased non-proportionally as compared to the ratio of ALG/KER in the blend, which explains the compatibility of ALG and KER over all blend ratios. However, the maximum compatibility between ALG and KER was found for the blend ratio 80:20 because its intensity dropped drastically compared to other blend ratios. The findings of the XRD study were able to support and justify the conclusion drawn by Jou et al (38).
SEM analysis
The surface morphology of the blend films was observed by SEM study and its results are shown in Figure 3. The native film of ALG (100 %) was prepared as a control (Fig. 3A). The native film of KER (100%) was not shown here because it was too fragile and cannot be considered as a film. The blend of ALG/KER plasticized by glycerol gives a homogeneous and smooth surface. It was found that the blend film was flexible, homogeneous, and semitransparent with a light yellow color; it possesses a compact structure without any cracks and pores (Fig. 4). The fracture surface (cross-sectional area) of the blend film (Figs. 3B1 and B2) confirms that the keratin fibers are not only present on the surface, but also throughout the polymer matrix (41). The SEM images in Figures 3C, D, E, and F represent the blend film with ratio 80:20, 70:30, 60:40, and 50:50, respectively. This explains why the increase in keratin content causes the formation of a rocky kind structure on the surface of the polymer matrix because of which the blend film becomes more rigid and less flexible. The outcome of the SEM study supported the results reported by researcher Wang et al (42). In similar studies, Hewage et al (43) discussed the film prepared from cowpea protein isolate, which has homogeneous, transparent, and flexible characteristics. The alginate/gelatin blend film was developed by Dong et al (44) as a drug delivery system and ciprofloxacin hydrochloride was used by them as a model drug to study its release rate. The SEM observation of the ALG/KER blend validates that both polymers are compatible with each other and are suitable for developing a blend film for biomaterial applications.
The surface morphology study of the ALG/KER blend films by SEM. (A) illustrates the control film of ALG; (B) shows blend film with ratio 90:10; (C), (D), (E), and (F) represent the blend film with ratio 80:20, 70:30, 60:40, and 50:50, respectively. All SEM images were taken at 500× magnification, except (B1) and (B2).
Still photographic images of ALG/KER blend films. The images (B), (C), (D), (E), and (F) represent the blend film with ratio 90:10, 80:20, 70:30, 60:40, and 50:50, respectively. Image (A) illustrates the blend film of native ALG (100%).
Tensile strength analysis
The mechanical characteristics of the blend film depend on the nature of polymer material used, their level of interaction, and even the processing methods used (39). The glycerol plasticized ALG/KER film expresses flexible characteristics along with the percentage of elongation at break and tensile strength shown in Figure 5. It was found that the tensile strength of the native ALG film has a maximum value but the percentage of elongation at break is lowest as depicted in Figure 5. However, the tensile strength and percent of elongation at break of the blend films was gradually decreased as the ratio of KER increased in the blend solution. The tensile strength and percent of elongation at break was observed to be highest for the blend ratio 90:10; it decreased gradually for the rest of the blend films. The observed result was in agreement with the discussions of previous work, which explain that the tensile strength is irreversibly proportional to the percent of elongation at break (29). Overall, the blend film with ratio 90:10 expressed a good combination of tensile strength 0.38 MPa as well as a percentage of elongation at break 59.5%. The mechanical strength obtained is lower with respect to the synthetic polymer blends (30), and yet it has enough strength for the development of biomaterials and scaffolds for tissue engineering applications (45).
The mechanical characteristics of ALG/KER blend films. The blend films with ratio 90:10 bear a good combination of tensile strength as well as percentage of elongation at break.
Degradation study of the blend film
The degradation study of the blend film was observed by calculating its weight loss percentage. The percentage of weight loss was observed 18.27 ± 1.25%, 47.73 ± 2.39%, 56.31 ± 1.23%, and 63.61 ± 3.07 % after weeks 1, 2, 3, and 4 of degradation treatment with PBS, respectively. After the fourth week of degradation it was observed that around 64% of the blend film’s initial weights was lost due to degradation treatment. The degradation properties of the blend film become significant as regards environmental issues. In addition, if the blend material is used as implants in tissue engineering then it should not present as permanent implants within the body (46) and must be degradable to allow cells to produce their own extracellular matrix (47).
Water retention capacity of the blend film
The ability to retain water by the fabricated blend film itself was observed to be 168 ± 5.94%, which indicates its hydrophilic nature. The hydrophilic characteristics of the blend material make it suitable to fabricate a biomaterial like hydrogel for drug delivery (48), scaffold for tissue engineering (49), and even to maintain the moisture of objects coated with the blend material (30).
Conclusions
A series of ALG/KER blend films plasticized with 2% glycerol were fabricated by the solution casting method. The experimental results of XRD, SEM, and other characteristics like mechanical strength, degradation rate, and the water retention capacity of the blend film revealed that polymer compatibility exists between ALG and KER and that the blend expresses the combined properties of their native polymers. The blend with a composition ratio of 80:20 is one of the best blends with respect to its compatibility parameter, since its intensity pattern changes drastically as discussed in the Results section. The blend with the ratio 90:10 is another one of the strongest candidates because it possesses the highest tensile strength (0.38 MPa) as well as a percentage of elongation of 59.5%, which was found to be suitable for biomaterial applications. The results of the present study suggest that the 2 polymers ALG and KER have the capability to be miscible with each other and can be fabricated in the form of film with enough tensile strength. The fabricated blend film can be a future substrate for fabrication of a range of biomaterials such as drug delivery vesicles, hydrogels, and scaffolding.
Acknowledgement
A special thanks to the Department of Metallurgical Engineering, National Institute of Technology Raipur, India, for conducting the experiment on XRD and SEM.
Disclosures
Financial support: The authors declare that the present work has been done without any financial support.
Conflict of interest: The authors declare they have no conflict of interest.
References
1.NawazMKaleem BalochMRehmanWInvestigating the compatibility of polymers in common solvent.J Chil Chem Soc2010559093Google Scholar
2.YeeAMaxwellMMechanical properties of polymer mixtures: Effect of compatibility.J Macromol Sci Part B198017543564Google Scholar
3.FioramontiSAPerezAAAríngoliEERubioloACSantiagoLGDesign and characterization of soluble biopolymer complexes produced by electrostatic self-assembly of a whey protein isolate and sodium alginate.Food Hydrocoll201435129136Google Scholar
4.Deniaud-BouëtEKervarecNMichelGTononTKloaregBHervéCChemical and enzymatic fractionation of cell walls from Fucales: insights into the structure of the extracellular matrix of brown algae.Ann Bot2014114612031216Google Scholar
5.BarbaAALambertiGRabbiaLGrassiMLarobinaDGrassiGModeling of the reticulation kinetics of alginate/pluronic blends for biomedical applications.Mater Sci Eng C Mater Biol Appl201437327331Google Scholar
6.KaassisAYAYoungNSanoNet al.Pulsatile drug release from electrospun poly(ethylene oxide)–sodium alginate blend nanofibres.J Mater Chem B2014214001407Google Scholar
7.ShenWHsiehYLBiocompatible sodium alginate fibers by aqueous processing and physical crosslinking.Carbohydr Polym2014102893900Google Scholar
8.PuguanJMCYuXKimHCharacterization of structure, physico-chemical properties and diffusion behavior of Ca-Alginate gel beads prepared by different gelation methods.J Colloid Interface Sci2014432109116Google Scholar
9.SunJTanHAlginate-based biomaterials for regenerative medicine applications.Materials (Basel)2013612851309Google Scholar
10.JiYChenJLvJLiZXingLDingSExtraction of keratin with ionic liquids from poultry feather.Separ Purif Tech2014132577583Google Scholar
11.KittrickJMCChenPBoddeSGYangWNovitskayaEEMeyersMAThe Structure, Functions, and Mechanical Properties of Keratin.JOM2012644449468Google Scholar
12.VasconcelosACavaco-PauloAThe use of keratin in biomedical applications.Curr Drug Targets201314612619Google Scholar
13.XingZCYuanJChaeWPKangIKKimSYKeratin nanofibers as a biomaterial.2010 Int Conf Nanotechnol Biosens IPCBEE2011:2120124http://www.ipcbee.com/vol2/28-Y10011.pdf Accessed August 4, 2015.Google Scholar
14.NairLSLaurencinCTBiodegradable polymers as biomaterials.Prog Polym Sci200732762798Google Scholar
15.MaskarinecSATirrellDAProtein engineering approaches to biomaterials design.Curr Opin Biotechnol200516422426Google Scholar
16.SierpinskiPGarrettJMaJet al.The use of keratin biomaterials derived from human hair for the promotion of rapid regeneration of peripheral nerves.Biomaterials2008291118128Google Scholar
17.HamidiMAzadiARafieiPHydrogel nanoparticles in drug delivery.Adv Drug Deliv Rev20086016381649Google Scholar
18.NwodoUUGreenEOkohAIBacterial exopolysaccharides: functionality and prospects.Int J Mol Sci201213111400214015Google Scholar
19.WnekGECarrMESimpsonDGBowlinGLElectrospinning of Nanofiber Fibrinogen Structures.Nano Lett20033213216Google Scholar
20.ElliottDEElectrospinning of gelatin (Doctoral dissertation, University of Reading).2013Google Scholar
22.JiangQReddyNZhangSRoscioliNYangYWater-stable electrospun collagen fibers from a non-toxic solvent and crosslinking system.J Biomed Mater Res A2013101A512371247Google Scholar
23.AraujoJPadrãoJSilvaJPet al.Processing and characterization of α-elastin electrospun membranes.Appl Phys, A Mater Sci Process201311512911298Google Scholar
24.RouseJGVan DykeMEA review of keratin-based biomaterials for biomedical applications.Materials (Basel)201039991014Google Scholar
25.Wrześniewska-tosikKKucharskaMFibrous Keratin-Containing Composite.Fibers and Textiles in Eastern Europe2008671113116http://www.fibtex.lodz.pl/article229.html Accessed August 4. 2015.Google Scholar
26.BaroneJRSchmidtWFPolyethylene reinforced with keratin fibers obtained from chicken feathers.Compos Sci Technol200565173181Google Scholar
27.LvRLiYLiJSet al.Effect of PLLA/Keratin Ratio on Mechanical and Physical Properties of Electrospun Nonwoven Fibrous Membrane.J Fiber Bioeng Informatics20081201208Google Scholar
28.PrasongSWasanTPreparation and Characterization of Hair Keratin/Gelatin Blend Films.Pak J Biol Sci201114351356Google Scholar
29.AluigiAVineisCVaresanoAMazzuchettiGFerreroFToninCStructure and properties of keratin/PEO blend nanofibres.Eur Polym J20084424652475Google Scholar
30.GuptaPNayakKKCharacteristics of protein-based biopolymer and its application.Polym Eng Sci2015553485498Google Scholar
31.YamauchiKYamauchiAKusunokiTKohdaAKonishiYPreparation of stable aqueous solution of keratins, and physiochemical and biodegradational properties of films.J Biomed Mater Res199631439444Google Scholar
32.OlivasGIBarbosa-CánovasGVAlginate–calcium films: Water vapor permeability and mechanical properties as affected by plasticizer and relative humidity.LWT - Food Sci Technol2008412359366Google Scholar
33.IdrisAVijayaraghavanRRanaUAPattiAFMacFarlaneDRDissolution and regeneration of wool keratin in ionic liquids.Green Chem20141628572864Google Scholar
34.LiSYangXHFabrication and Characterization of Electrospun Wool Keratin/Poly(vinyl alcohol) Blend Nanofibers.Adv Mater Sci Eng2014201417Google Scholar
35.NagpalMSinghSKMishraDSynthesis characterization and in vitro drug release from acrylamide and sodium alginate based superporous hydrogel devices.Int J Pharm Investig201333131140Google Scholar
36.AluigiAZoccolaMVineisCToninCFerreroFCanettiMStudy on the structure and properties of wool keratin regenerated from formic acid.Int J Biol Macromol200741266273Google Scholar
37.SchorRKrimmSStudies on the Structure of Feather Keratin: I. X-Ray Diffraction Studies and Other Experimental Data.Biophys J19611467487Google Scholar
38.JouJHHuangPTX-Ray Diffraction Study of Polyimide Blends Compatibility.Polym J199022909918Google Scholar
39.TianHXuGYangBGuoGMicrostructure and mechanical properties of soy protein/agar blend films: Effect of composition and processing methods.J Food Eng20111072126Google Scholar
40.SuJFHuangZYuanXYWangXYLiMStructure and properties of carboxymethyl cellulose/soy protein isolate blend edible films crosslinked by Maillard reactions.Carbohydr Polym2010791145153Google Scholar
41.BaroneJRPolyethylene/keratin fiber composites with varying polyethylene crystallinity.Compos, Part A Appl Sci Manuf20053615181524Google Scholar
42.WangMZhaoTWangGZhouJBlend films of human hair and cellulose prepared from an ionic liquid.Text Res J20148413151324Google Scholar
43.HewageSVithanarachchiSMPreparation and characterization of biodegradable polymer films from cowpea (Vigna unguiculata) protein isolate.J Natl Sci Found Sri Lanka20093715359Google Scholar
44.DongZWangQDuYAlginate/gelatin blend films and their properties for drug controlled release.J Membr Sci20062803744Google Scholar
45.BongSHanYSangMHwaSMooYStudy of gelatin-containing artificial skin V: fabrication of gelatin scaffolds using a salt-leaching method.Biomaterials20052619611968Google Scholar
46.O’BrienFJBiomaterials & scaffolds for tissue engineering.Mater Today2011148895Google Scholar
47.BabenseeJEAndersonJMMcIntireLVMikosAGHost response to tissue engineered devices.Adv Drug Deliv Rev199833111139Google Scholar
48.MishraRKSinghalJPDattM. DattBanthiaAKAmidated pectin based hydrogels: synthesis, characterization and cytocompatibility study.J Appl Biomater Biomech2007528894Google Scholar
49.ChangNJJhungYRYaoCKYehMLHydrophilic gelatin and hyaluronic acid-treated PLGA scaffolds for cartilage tissue engineering.J Appl Biomater Funct Mater201311e45e52Google Scholar
Department of Biotechnology, National Institute of Technology Raipur, Chhattisgarh - India
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