Effect Of Freezing Methods On The Properties Of Lyophilized Porous Silk Fibroin Membranes

Silk fibroin is a fibrous protein that has been extensively studied for application in the biomedical field, and has been used as a scaffold for bone tissue engineering. Biomaterials made of proteins are prone to physical and chemical degradation during storage; lyophilization, a drying method that consists of freezing and drying steps, is known to promote minimal changes in structure and biological activity of biomaterials. This study evaluates the effect of freezing methods on the properties of lyophilized porous silk fibroin membranes. The membranes were obtained from silk fibroin solution, frozen in liquid nitrogen or ultrafreezer, lyophilized, and then characterized by XRD, FTIR, TGA, DSC and SEM. Although the membranes presented similar physical, chemical and microstructural characteristics, quench freezing with liquid nitrogen, followed by lyophilization, promoted collapse of the membranes, while slow cooling performed by ultrafreezer preserved membrane integrity.122233237Tamada, Y., New process to form a silk fibroin porous 3-D structure (2005) Biomacromolecules, 6 (6), pp. 3100-3106Park, K., Jung, S., Lee, S., Min, B., Park, W., Biomimetic nanofibrous scaffolds: Preparation and characterization of chitin/silk fibroin blend nanofibers (2006) International Journal of Biological Macromolecules, 38 (3-5), pp. 165-173Sashina, E., Bochek, A., Novoselov, N., Kirichenko, D., Structure and solubility of natural silk fibroin (2006) Russian Journal of Applied Chemistry, 79 (6), pp. 869-876Vasconcelos, A., Freddi, G., Cavaco-Paulo, A., Biodegradable materials based on silk fibroin and keratin (2008) Biomacromolecules, 9 (4), pp. 1299-1305Roy, I., Gupta, M., Freeze-drying of proteins: Some emerging concerns (2004) Biotechnology and Applied Biochemistry, 39 (2), pp. 165-177Tang, X., Pikal, M., Design of freeze-drying processes for pharmaceuticals: Practical advice (2004) Pharmaceutical Research, 21 (2), pp. 191-200Sablani, S., Influence of shelf temperature on pore formation in garlic during freeze-drying (2006) Journal of Food Engineering, 80 (1), pp. 68-79Luthra, S., Obert, J., Kalonia, D., Pikal, M., Impact of critical process and formulation parameters affecting in-process stability of lactate dehydrogenase during the secondary drying stage of lyophilization: A mini freeze dryer study (2007) Journal of Pharmaceutical Sciences, 96 (9), pp. 2242-2250Wang, W., Lyophilization and development of solid protein pharmaceuticals (2000) International Journal of Pharmaceutics, 203 (1-2), pp. 1-60Rambhatla, S., Ramot, R., Bhugra, C., Pikal, M., Heat and mass transfer scale-up issues during freeze drying: II. control and characterization of the degree of supercooling (2004) AAPS PharmSciTech, 5 (4), pp. e58Chang, B., Kendrick, B., Carpenter, J., Surface-induced denaturation of proteins during freezing and its inhibition by surfactants (1996) Journal of Pharmaceutical Sciences, 85 (12), pp. 1325-1330Searles, J., Carpenter, J., Randolph, T., The ice nucleation temperature determines the primary drying rate of lyophilization for samples frozen on a temperature-controlled shelf (2001) Journal of Pharmaceutical Sciences, 90 (7), pp. 860-871Kim, H., Kim, U., Leisk, G., Bayan, C., Georgakoudi, I., Kaplan, D., Bone regeneration on macroporous aqueous-derived silk 3-D scaffolds (2007) Macromolecular Bioscience, 7 (5), pp. 643-655Wang, Y., Rudym, D., Walsh, A., Abrahamsen, L., Kim, H.J., Kim, H.S., In vivo degradation of three-dimensional silk fibroin scaffolds (2008) Biomaterials, 29 (24-25), pp. 3415-3428Ki, C., Park, S., Kim, H., Jung, H., Woo, K., Lee, J., Development of 3-D nanofibrous fibroin scaffold with high porosity by electrospinning: Implications for bone regeneration (2008) Biotechnology Letters, 30 (3), pp. 405-410Lv, Q., Feng, Q., Preparation of 3-D regenerated fibroin scaffolds with freeze drying method and freeze drying/foaming technique (2006) Journal of Materials Science: Materials in Medicine, 17 (12), pp. 1349-1356Beppu M, Polakiewicz B, Nogueira G. PI: 0601975-72006. INPI/Brazil2006Li, M., Lu, S., Wu, Z., Tan, K., Minoura, N., Kuga, S., Structure and properties of silk fibroin-poly(vinyl alcohol) gel (2002) International Journal of Biological Macromolecules, 30 (2), pp. 89-94Lin, F., Li, Y., Jin, J., Cai, Y., Wei, K., Yao, J., Deposition behavior and properties of silk fibroin scaffolds soaked in simulated body fluid (2008) Materials Chemistry and Physics, 111 (1), pp. 92-97Um, I., Kweon, H., Park, Y., Hudson, S., Structural characteristics and properties of the regenerated silk fibroin prepared from formic acid (2001) International Journal of Biological Macromolecules, 29 (2), pp. 91-97Zoccola, M., Aluigi, A., Vineis, C., Tonin, C., Ferrero, F., Piacentino, M.G., Study on cast membranes and electrospun nanofibers made from keratin/fibroin blends (2008) Biomacromolecules, 9 (10), pp. 2819-2825Kim, H.J., Kim, U., Kim, H.S., Li, C., Wada, M., Leisk, G., Bone tissue engineering with premineralized silk scaffolds (2008) Bone, 42 (6), pp. 1226-1234Bhatnagar, B., Bogner, R., Pikal, M., Protein stability during freezing: Separation of stresses and mechanisms of protein stabilization (2007) Pharmaceutical Development and Technology, 12 (5), pp. 505-52

Influence Of Acetylation On In Vitro Chitosan Membrane Biomineralization

In a previous work of this research group, we studied the in vitro calcification of dense and porous chitosan membranes. Chemical modifications had been promoted, but further investigations were needed to better understand the role of some chemical groups in the process of calcification. In the present study, we proposed the acetylation of the already-molded chitosan membranes, producing a "pseudo-chitin", to be used in calcification. The acetylated chitosan was submitted to mineralization by soaking the membranes in simulated body fluids (SBF) with 1x and 1.5x the concentration of ions found in human serum, for 7 days at 36.5°C. Morphological characterization was performed using SEM and compositional analyses were done using SEM-EDX and FTIR-ATR techniques. The results showed that acetyl groups induce calcification, forming deposits that present a Ca:P ratio different of those formed on pristine chitosan.254-256311314Calvert, P., Rieke, P., (1996) Chem. Mater., 8, p. 1715Beppu, M.M., Santana, C.C., (2000) Key Eng. Mater., 125-129, p. 34Beppu, M.M., Santana, C.C., (2002) Mater. Sci., 5, p. 47Beppu, M.M., (1999) Estudo da Calcificação in Vitro da Quitosana, , PhD thesis - FEQ - State University of Campinas. BrazilHirano, S., (1987) Industrial Polysaccharides, , Elsevir Science Publishers. AmsterdamZhang, S., Gonsalves, K.E., (1995) J. Appl. Polym. Sci., 56, p. 68

In Vitro Biomineralization Of Chitosan

The influence of chemical treatments of porous and non-porous chitosan membranes on biomineralization was studied. These treatments are: 1) the crosslinking using glutaraldehyde and 2) the adsorption of poly(acrylic acid) (PAA) on chitosan. The first one blocks chitosan amino groups, inducing a more hydrophobic character to the substrate, and the second one turns the membrane surface polyanionic instead of the polycationic natural character of chitosan. Substrates (membranes) of chitosan treated in both ways were used to undergo mineralization by soaking them in simulated body fluids (SBF), with 1x or 1.5x the concentration of ions found in human serum, for 7 at 36.5°C. SEM-EDS and FTIR-ATR techniques showed that glutaraldehyde tends to inhibit calcium compound deposition on substrates while PAA induces a more homogeneous and intense deposition.192-1953134Pathak, Y., Shoen, F.J., Levy, R.J., Pathologic calcification of biomaterials (1996) Biomaterials Science, An Introduction to Materials in Medicine, pp. 272-282. , Ed. Ratner, B.D., Hoffman, A.S., Schoen, F.J. e Lemons, J.E., Academic Press, California-USASandford, P.A., Chitosan: Commercial uses and potential applications (1989) Chitin and Chitosan, pp. 51-69. , Ed. Skjaek-Braek, G et al., Elsevier Applied Science, New YorkGolomb, G., Wagner, D., (1991) Biomaterials, 12, p. 397Mucalo, M.R., Toriyama, M., Yokogawa, Y., Suzuki, T., Kawamoto, Y., Nagata, F., Nishizawa, K., (1995) J. Mater. Sci. Mater. Medicine, 6, pp. 409-419Tanahashi, M., Yao, T., Kokubo, T., Minoda, M., Miyamoto, T., Nakamura, T., Yamamuro, T., (1995) J. Mater. Sci. Mater. Medicine, 6, pp. 319-326Koutsopoulos, S., Kontogeorgergou, A., Ptroheilos, J., Dalas, E., (1998) J. Mater. Sci. Mater. Medicine, 9, pp. 421-424Golomb, G., (1992) J. Mater. Sci. Mater. Medicine, 3, pp. 272-377Kokubo, T., Ito, S., Huang, Z.T., Hayashi, T., Sakka, S., Kitsugi, T., Yamamuro, T., (1990) Journal of Biomed, Mater. Res., 24, pp. 331-343Davies, J.E., Mechanisms of endosseous integration (1998) Conference, 1st COLAOB, , Belo-Horizonte, BrazilBeppu, M.M., Estudo da Calcificação in Vitro de Quitosana, , PhD Thesis in print. Unicamp Brazi

Layer-by-layer Thin Films Of Alginate/chitosan And Hyaluronic Acid/chitosan With Tunable Thickness And Surface Roughness

Layer-by-layer (LbL) is a bottom-up technique used for construction of films with selfassembly and self-organizing properties. In most cases, the fundamental driving force for the formation of these films is originated from the electrostatic interaction between oppositely charged species. The charged segments of polyelectrolytes behave as small building units and their orientation and position can be designed to target structures of great complexity. Furthermore, the technique enables the use of various materials, including natural polymers. In this work, we chose the cationic biopolymer chitosan (CHI) and the negative polyelectrolytes sodium alginate (ALG) and hyaluronic acid (HA). The aim of this study was to evaluate the effect of ionic strength (0 versus 200 mM) and pH (3 versus 5) on ALG/CHI and HA/CHI nanostructured multilayered thin films properties. From profilometry and atomic force microscopy (AFM) analyses, changes in thickness and roughness of the coatings were monitored. The presence of salt in polyelectrolyte solutions induced the polymer chains to adopt conformations with more loops and tails and this arrangement in solution was transmitted to films, resulting in rougher surfaces. Furthermore, the film thickness can be precisely controlled by adjusting the pH of the polyelectrolyte solution. The variation of these parameters shows that it is possible to molecularly control chemical and structural properties of nanostructured coatings, thus opening up new possibilities of application (e.g. cell adhesion). © (2014) Trans Tech Publications, Switzerland.783-78612261231CDMM,Dynamic systems Inc.,et al,National Science Foundataion (NSF),Office of Naval Research (ONR),POSCODecher, G., Nanoassemblies, F., Toward Layered Polymeric Multicomposites (1997) Science, 277, pp. 1232-1237Voigt, U., Jaeger, W., Findenegg, G.H., Klitzing, R.V., Charge Effects on the Formation of Multilayers Containing Strong Polyelectrolytes (2003) The Journal of Physical Chemistry B, 107, pp. 5273-5280Delcea, M., Möhwald, H., Skirtach, A.G., Stimuli-responsive LbL capsules and nanoshells for drug delivery (2011) Advanced Drug Delivery Reviews, 63, pp. 730-747Vasconcellos, F.C., Swiston, A.J., Beppu, M.M., Cohen, R.E., Rubner, M.F., Bioactive Polyelectrolyte Multilayers: Hyaluronic Acid Mediated B Lymphocyte Adhesion (2010) Biomacromolecules, 11, pp. 2407-2414Etienne, O., Gasnier, C., Taddei, C., Voegel, J.-C., Aunis, D., Schaaf, P., Metz-Boutigue, M.-H., Egles, C., Antifungal coating by biofunctionalized polyelectrolyte multilayered films (2005) Biomaterials, 26, pp. 6704-6712Lichter, J.A., van Vliet, K.J., Rubner, M.F., Design of Antibacterial Surfaces and Interfaces: Polyelectrolyte Multilayers as a Multifunctional Platform (2009) Macromolecules, 42, pp. 8573-8586Tsuge, Y., Kim, J., Sone, Y., Kuwaki, O., Shiratori, S., Fabrication of transparent TiO2 film with high adhesion by using self-assembly methods: Application to super-hydrophilic film (2008) Thin Solid Films, 516, pp. 2463-2468Richert, L., Lavalle, P., Payan, E., Shu, X., Prestwich, G., Stoltz, J., Schaaf, P., Picart, C., Layer by layer buildup of polysaccharide films: Physical chemistry and cellular adhesion aspects (2004) Langmuir, 20, pp. 448-458Rinaudo, M., Main properties and current applications of some polysaccharides as biomaterials (2008) Polymer International, 57, pp. 397-430Alves, N.M., Picart, C., Mano, J.F., Self Assembling and Crosslinking of Polyelectrolyte Multilayer Films of Chitosan and Alginate Studied by QCM and IR Spectroscopy (2009) Macromolecular Bioscience, 9, pp. 776-785Jin, R.-H., Yuan, J.-J., Biomimetically Controlled Formation of Nanotextured Silica/Titania Films on Arbitrary Substrates and Their Tunable Surface Function (2009) Advanced Materials, 21, pp. 3750-3753Lavalle, P., Gergely, C., Cuisinier, F.J.G., Decher, G., Schaaf, P., Voegel, J.C., Picart, C., Comparison of the Structure of Polyelectrolyte Multilayer Films Exhibiting a Linear and an Exponential Growth Regime: An in Situ Atomic Force Microscopy Study (2002) Macromolecules, 35, pp. 4458-4465Box, G.E.P., Hunter, W.G., Hunter, J.S., (1978) Statistics For Experimenters: An Introduction to Design, Data Analysis, , and model building, WileyShiratori, S.S., Rubner, M.F., PH-Dependent Thickness Behavior of Sequentially Adsorbed Layers of Weak Polyelectrolytes (2000) Macromolecules, 33, pp. 4213-4219Ikeda, A., Takemura, A., Ono, H., Preparation of low-molecular weight alginic acid by acid hydrolysis (2000) Carbohydrate Polymers, 42, pp. 421-425Voigt, U., Khrenov, V., Thuer, K., Hahn, M., Jaeger, W., von Klitzing, R., The effect of polymer charge density and charge distribution on the formation of multilayers (2003) Journal of Physics- Condensed Matter, 15, pp. S213-S218Dubas, S.T., Schlenoff, J.B., Polyelectrolyte Multilayers Containing a Weak Polyacid: Construction and Deconstruction (2001) Macromolecules, 34, pp. 3736-3740Rojas, O.J., Claesson, P.M., Muller, D., Neuman, R.D., The Effect of Salt Concentration on Adsorption of Low-Charge-Density Polyelectrolytes and Interactions between Polyelectrolyte- Coated Surfaces (1998) Journal of Colloid and Interface Science, 205, pp. 77-88McAloney, R.A., Sinyor, M., Dudnik, V., Goh, M.C., Atomic Force Microscopy Studies of Salt Effects on Polyelectrolyte Multilayer Film Morphology (2001) Langmuir, 17, pp. 6655-6663Ren, K., Wang, Y., Ji, J., Lin, Q., Shen, J., Construction and deconstruction of PLL/DNA multilayered films for DNA delivery: Effect of ionic strength (2005) Colloids and Surfaces B: Biointerfaces, 46, pp. 63-69Bohmer, M.R., Evers, O.A., Scheutjens, J.M.H.M., Weak polyelectrolytes between two surfaces: Adsorption and stabilization (1990) Macromolecules, 23, pp. 2288-2301Fery, A., Schöler, B., Cassagneau, T., Caruso, F., Nanoporous Thin Films Formed by Salt- Induced Structural Changes in Multilayers of Poly(acrylic acid) and Poly(allylamine) (2001) Langmuir, 17, pp. 3779-378

Preface: 10th Brazilian Meeting On Adsorption

[No abstract available

In Situ X-ray Diffraction Study Of Phase Development During Hardening Of β-tricalcium Phosphate Bone Cements With Chitosan

The aim of this work was to study the phase transformation during the setting reaction of beta tricalcium phosphate (β-TCP) and phosphoric acid with chitosan solution added. To follow the kinetics of the phase transformation, two methods were used: x-ray diffraction (XRD) was used to study the phase evolution during the hardening process in real time, and was also used in samples where the reaction was supposedly stopped in different times using acetone, as indicated in literature. The setting reaction occurs so fast that the phase transformation could not be observed, but it was possible to invalidate the second mentioned method for this system, as it induces the final product dicalcium phosphate dihydrate DCPD (brushite) to be converted into his anhydrous form dicalcium phosphate DCP (monetite). The addition of chitosan in order to improve biocompatibility was successfully done, it could be observed that chitosan inhibits brushite crystallization in the first moment of the reaction, but the final product was not affected by it. © (2014) Trans Tech Publications, Switzerland.587109114Galembeck, F., Lima, E.C.O., Beppu, M.M., Polyphosphate nanoparticles and gels-from macroscopic monoliths to nanoparticles (1996) Nato Advanced Science Institute Series, 12, pp. 267-279Legeros, R.Z., Chohayeb, A., Shulman, A., Apatitic calcium phosphates: Possible dental restorative materials (1982) J. Dent. Res, 61Dorozhkin, S.V., Calcium orthophosphate cements and concretes (2009) Materials, 27, pp. 221-291Tonoli, M.S., Leal, C.V., Zavaglia, C.A., Beppu, M.M., Development and characterization of β-tricalcium phosphate cements containing chitosan (2006) Key Engineering Materials, 309, pp. 845-848Beppu, M.M., Santana, C.C., PAA influence on chitosan membrane calcification (2003) Materials Science and Engineering C, 23, pp. 651-658Aimoli, C.G., Beppu, M.M., Precipitation of calcium phosphate and calcium carbonate induced over chitosan membranes: A quick method to evaluate the influence of polymeric matrix on heterogeneous calcification (2006) Colloids and Surfaces B, 53, pp. 15-22Aimoli, C.G., Torres, M.A., Beppu, M.M., Investigations into the early stages of "in vitro" calcification on chitosan films (2006) Materials Science and Engineering C, 26, pp. 78-86Beppu, M.M., Aimoli, C.G., Influence on in vitro chitosan membrane biomineralization (2004) Key Engineering Materials, 254, pp. 311-314Aimoli, C.G., Nogueira, G.M., Nascimento, L.S., Lyiophilized bovine pericardium treated with a phenetilamine-diepoxide as na alternative to preventing calcification of cardiovascular bioprosthesis: Preliminary results (2007) Artificial Organs, 31, pp. 278-283Bohner, M., Reactivity of calcium phosphate cements (2007) Journal of Materials Chemistry, 17, pp. 3980-3986Rau, J.V., Energy dispersive X-ray diffraction study of phase development during hardening of calcium phosphate bone cements with addition of chitosan (2008) Acta Biomaterialia, 4, pp. 1089-1094Grover, L., Temperature dependent setting kinetics and mechanical properties of β-TCP-pyrophosphoric acid bone cement (2005) J. Mater. Chem, 15, pp. 4955-4962Ginebra, M.P., Desarrolo y caracterización de un cemento óseo basado en fosfato tricálcico-α para aplicaciones quirurgicas (1996) Dissertação (Doutorado em Ciências, Especialidade Física)-Departament de Ciências Dels Materials i Enginyeria Metalurgica, , Universitat Politécnica de Catalunya 1996Bohner, M., Lemaître, J., Hydraulic properties of tricalcium phosphate-phosphoric acid-water mixtures (1993) Journal of Materials Science Materials in Medicine, 8Jinlong, N., Zhenxi, Z., Dazong, J., Investigation of phase evolution during the thermochemical synthesis of tricalcium phosphate (2002) Journal of Materials Synthesis and Processing, 9, pp. 235-240ASTM-C266-04: Standard Test Method for Time of Setting of Hydraulic-cement Paste by Gillmore NeedlesDosen, A., Giese, R.F., Thermal decomposition of brushite CaHPO4, 2H 2O to monetite CaHPO4 and the formation of an amorphous phase (2011) American Minearalogist, 96, pp. 368-373Bohner, M., Merkle, H.P., Lemaître, J., In vitro aging of a calcium phosphate cement (2000) Journal of Materials Science Materials in Medicine, 11, pp. 155-16

Evaluation Of In Vitro Calcification Of Pristine And Sulfonated Chitosan For Use On Stents

[No abstract available]26SUPPL.6155Beppu, M.M., Santana, C.C., (2003) Mater. Sci. Eng, 23, p. 651Amiji, M.M., (1998) Colloids Surfaces B: Biointerfaces, 10, pp. 263-271Aimoli, C.G., Torres, M.A., Beppu, M.M., (2006) Mater Sci and Eng C, 26, pp. 78-86Park, K.D., Lee, W.K., (1997) Biomaterials, 18, pp. 47-51Lee, W.K., Park, K.D., (2001) J Biomed Mater Res (Appl Biomater), 58, pp. 27-3

Development and characterization of membranes derived from SF/GLY/58S hybrid xerogels for the release of inorganic ions as an osteogenic stimulus for bone regeneration

The ternary membrane-forming system based on the silk fibroin (SF), glycerol (GLY) and sol-gel precursor of 58S bioactive glass (BG) was studied for the preparation of novel and multifunctional hybrid membranes. The morphology of membranes was observed by scanning electron microscopy (SEM) and spectral imaging, by X-ray mapping technique, were performed in order to investigate the chemical homogeneity of elements. The results show that there is a critical limit for the concentration of GLY and BG for formation of flexible membranes and without a phase separation. XRD and FTIR data showed that the GLY and BG in the silk matrix modifies the short- and intermediate-range order resulting in changes in the silk conformation, i.e., SF molecules are gradually transformed from random coils toward more stable structures – Silk I and Silk II (β-sheets). The solubility study showed that the hybrid membranes have an excellent chemical stability, confirming that the incorporation of inorganic species in the matrix allowed the preparation of novel well-controlled water-soluble membranes. The release profiles of Ca, P and Si confirmed ability of hybrid membranes to deliver controlled inorganic species, which in critical concentration, control the gene expression of osteoblasts and influences cell metabolism and function116425437COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP33003017034P82010/05394-9We are very grateful to Professor Celso Aparecido Bertran – Institute of Chemistry, University of Campinas – for hosting part of this research in his laboratory. The authors acknowledge the use of the analytical instrumentation facility at Institute of Chemistry – University of Campinas. This work is fully supported by Brazilian Federal Agency for the Support and Evaluation of Graduate Education – CAPES (Grant 33003017034P8) and the Sao Paulo Research Foundation – FAPESP (Grant 2010/05394-9

Improvement Of Collagen Hydrogel Scaffolds Properties By The Addition Of Konjac Glucomannan

Collagen gels have been investigated for a number of applications in tissue engineering because of their excellent biological properties. However, their limited mechanical behavior represents a major bottleneck for clinical use, especially for vascular tissue engineering. The targeting of their mechanical properties may be envisaged by the addition of other biopolymers, such as konjac glucomannan (KGM), a neutral high-molecular weight polysaccharide extracted from the tubers of Amorphophallus konjac, which has already been studied for biomedical applications due to its biocompatibility and biodegradable activity. In the present study, reconstituted collagen gels were prepared at pH 10 and room temperature, by mixing collagen with NaOH, NaCl and 0.05 to 0.2% of KGM. Collagen fibrillogenesis was monitored by spectrophotometric analysis at 310 nm. Gel samples were analyzed by compression tests, FTIR and SEM. Comparing to the control, the addition of KGM reduced the half-time (t1/2) of gelation from ca. 3 h to 2 h and the mechanical tests showed increases in the compressive strain energy of up to 3 times, and in compressive modulus of almost 4 times. Scanning electron images of collagen gel samples with KGM revealed the presence of micro-domains of KGM in the collagen matrix, revealing a phase-separated scaffold for vascular tissue engineering. © (2012) Trans Tech Publications, Switzerland.409187192The Minerals, Metals and Materials Society (TMS),NSFGil, E.S., Spontak, R.J., Hudson, S.M., (2005) Macromol. Biosci., 5, p. 702Wang, X., Kluge, J.A., Leisk, G.G., Kaplan, D.L., (2008) Biomaterials, 29, p. 1054Mandal, B.B., Kapoor, S., Kundu, S.C., (2009) Biomaterials, 30, p. 2826Habermehl, J., Skopinska, J., Boccafoschi, F., Sionkowska, A., Kaczmarek, H., Laroche, G., Mantovani, D., (2005) Macromol. Biosci., 5, p. 821Rajan, N., Habermehl, J., Cote, M.-F., Doillon, C.J., Mantovani, D., (2006) Nat. Protoc., 1, p. 2753Nam, K., Kimura, T., Funamoto, S., Kishida, A., (2010) Acta Biomater., 6, p. 403Couet, F., Rajan, N., Mantovani, D., (2007) Macromol. Biosci., 7, p. 701Achilli, M., Mantovani, D., (2010) Polymers, 2, p. 664Nishinari, K., (2000) Dev. Food Sci., 41, p. 309Alvarez-Mancenido, F., Landin, M., Martinez-Pacheco, R., (2008) Eur. J. Pharm. Biopharm., 69, p. 573Chen, J., Liu, C., Chen, Y., Chen, Y., Chang, P.R., (2008) Carbohydr. Polym., 74, p. 946Fan, J., Wang, K., Liu, M., He, Z., (2008) Carbohydr. Polym., 73, p. 241Xu, X., Li, B., Kennedy, J.F., Xie, B.J., Huang, M., (2007) Carbohydr. Polym., 70, p. 192Ye, X., Kennedy, J.F., Li, B., Xie, B.J., (2006) Carbohydr. Polym., 64, p. 532Lu, J., Wang, X., Xiao, C., (2008) Carbohydr. Polym., 73, p. 427Wang, B., Jia, D.-Y., Ruan, S.-Q., Qin, S., (2007) J. Appl. Polym. Sci., 106, p. 327Wang, B., Wang, K., Dan, W., Zhang, T., Ye, Y., (2006) J. Biomed. Eng., 23, p. 102. , Sheng Wu Yi Gong Cheng Xue Za ZhiChen, H.-B., Hong, D.F., Lei, L., Pan, X.-H., Chen, Q.-H., (2009) J. Kunming Univ. Sci. Technol., 9Liu, X., Wang, K., Ding, Y., He, X., Wang, B., (2005) J. Biomed. Eng., 22, p. 1004. , Sheng Wu Yi Gong Cheng Xue Za ZhiDave, V., Sheth, M., McCarthy, S.P., Ratto, J.A., Kaplan, D.L., (1998) Polymer, 39, p. 1139Tenni, R., Sonaggere, M., Viola, M., Bartolini, B., Tira, M.E., Rossi, A., Orsini, E., Ottani, V., (2006) Micron, 37, p. 640Rathi, A.N., Padmavathi, S., Chandrakasan, G., (1989) Biochem. Med. Metab. Biol., 42, p. 209Petibois, C., Gouspillou, G., Wehbe, K., Delage, J.-P., Deleris, G., (2006) Anal. Bioanal. Chem., 386, p. 1961Chen, L.G., Liu, Z.-L., Zhuo, R.-X., (2005) Polymer, 46, p. 6274An, N.T., Dong, N.T., Dung, P.L., Thien, D.T., (2011) Carbohydr. Polym., 83, p. 645Wen, X., Wang, T., Wang, Z., Li, L., Zhao, C., (2008) Int. J. Biol. Macromol., 42, p. 256Gaaloul, S., Corredig, M., Turgeon, S.L., (2009) J. Food Eng., 95, p. 254Harrington, J.C., Morris, E.R., (2009) Food Hydrocolloids, 23, p. 32

Thermal Treatment Effects On Biopolymer Multilayered Thin Films

Sterilization is very important for the use of biomaterials in the medical field. This work describes the preparation of chitosan/carboxymethylcellulose thin films with the layer-by-layer deposition technique, and the investigation on the effects that thermal treatments have on them during sterilization. The influence of different heating and sterilization methods on the chemical and physical structure of biopolymer thin films composed of chitosan and carboxymethylcellulose was evaluated. Films were heated in an oven at specified temperatures or autoclaved and their characteristics analyzed with contact angle, profilometry, FTIR, anionic dye uptake and UV-Vis measurements. Results show that, depending on the heating conditions, these thin films may undergo the Maillard reaction that turns the films from being transparent to brownish in color. This reaction may lead to a decrease in the free hydroxyl groups of both carboxymethylcellulose and chitosan and free ammonium groups of chitosan - consequently leading to changes in hydrophilicity and wettability of the film. Temperature effects on the characteristics of the synthetic pre-layer coating composed of poly(diallyldimethylammonium chloride) and poly (sodium 4-styrene-sulfonate) - used to provide a high cationic surface for the deposition of the biopolymer films - were also observed. These findings are of practical interest because biopolymer thin films find a great number of applications where sterilization is a must, such as clinical and medical applications and in the areas of materials science and biotechnology. © (2012) Trans Tech Publications, Switzerland.409181186The Minerals, Metals and Materials Society (TMS),NSFTang, Z.Y., Wang, Y., Podsiadlo, P., Kotov, N.A., (2006) Advanced Materials, 18, pp. 3203-3224Such, G.K., Johnston, A.P.R., Caruso, F.F., (2011) Chemical Society Reviews, 40, pp. 19-29Kasemo, B., (2002) Surface Science, 500, pp. 656-677Tuong, S.D., Lee, H., Kim, H., (2008) Macromolecular Research, 16, pp. 373-378Ramos, A.P., Doro, F.G., Tfouni, E., Goncalves, R.R., Zaniquelli, M.E.D., E, D.M., (2008) Thin Solid Films, 516, pp. 3256-3262Decher, G., Hong, J.D., Schmitt, J., (1992) Thin Solid Films, 210, pp. 831-835Vasconcellos, F.C., Swiston, A.J., Beppu, M.M., Cohen, R.E., Rubner, M.F., (2010) Biomacromolecules, 11, pp. 2407-2414Berg, M.C., Yang, S.Y., Hammond, P.T., Rubner, M.F., (2004) Langmuir, 20, pp. 1362-1368Su, J.F., Huang, Z., Yuan, X.Y., Wang, X.Y., Li, M., (2010) Carbohydrate Polymers, 79, pp. 145-153Umemura, K., Kawai, S., (2008) Journal of Applied Polymer Science, 108, pp. 2481-2487Tanaka, M., Huang, J.R., Chiu, W.K., Ishizaki, S., Taguchi, T., (1993) Nippon Suisan Gakkaishi, 59, pp. 1915-1921Umemura, K., Mihara, A., Kawai, S., (2010) Journal of Wood Science, 56, pp. 387-394Wang, J.W., Hon, M.H., (2003) Journal of Biomaterials Science-Polymer Edition, 14, pp. 119-137Porcel, C., Lavalle, P., Ball, V., Decher, G., Senger, B., Voegel, J.C., Schaaf, P., (2006) Langmuir, 22, pp. 4376-4383Radeva, T., Grozeva, M., (2005) Journal of Colloid and Interface Science, 287, pp. 415-421Tan, H.L., McMurdo, M.J., Pan, G.Q., Van Patten, P.G., (2003) Langmuir, 19, pp. 9311-9314Von Klitzing, R., (2006) Physical Chemistry Chemical Physics, 8, pp. 5012-5033Boyan, B.D., Hummert, T.W., Dean, D.D., Schwartz, Z., (1996) Biomaterials, 17, pp. 137-14