Synthesis Of Gelatin Cryogels

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Gelatin cryogel sheets (5%) were synthesized using glutaraldehyde as the cross-linker. The aldehyde groups of glutaraldehyde form covalent imine bonds with amino groups of gelatin. Initially different concentrations of gelatin were used (4%, 5%, 6% and 8% respectively). On physical examination of the cryogels produced with these concentrations, it was observed that at higher concentration of gelatin polymer (8%) the rate of polymerization was very fast and hence cryogel sheets formed were not proper. As the percentage of gelatin was increased the amount of cross-linker required was low i.e., the amount of cross-linker required decreases with increase in monomer concentration. Increase in polymer concentration also leads to less elasticity in the cryogel. Standardizations done for the synthesis of optimum concentrations of Gelatin and glutaraldehyde required is given in Table 1.1.
Gels with low gelatin concentrations were fragile and had low mechanical strength. Concentration of gelatin was optimized to be 5% which satisfied the properties of an ideal scaffold for skin tissue engineering. Gelation does not occur in the absence of chemical cross-linker i.e. glutaraldehyde which indirectly indicates the absence of physical cross-linking in gelatin. The mechanical strength of the cryogels increased with increase in gelatin concentrations. It was observed that as the total concentration of polymer precursors was increased from 4% to 8%, glutaraldehyde requirement for synthesizing optimum cryogel decreased from 1.0% to 0.1% (Table 1.1). This result can be better explained by understanding the well studied aspect of cryogelation that in moderately-frozen solutions, dissolved substances concentrate in the regions of non-frozen solvent (un...

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...ty of these scaffolds in skin tissue engineering as most of the skin cells like fibroblasts, keratinocytes etc., are smaller in size when compared to the pores. Therefore cells migrate and proliferate freely on these scaffolds along with the production of extracellular matrix. Furthermore, large and interconnected porous network facilities the diffusion of nutrients together with efficient gaseous exchange and is important for cell survival. As we run the in vitro experiments in the presence of media it is important to understand the variation in the pore size and diameter when the scaffold absorbs water or any other liquid. Pore size of the gelatin cryogel was in the range of 10-100 µm in swollen state. As evident from the results obtained even after the absorption of water the matrices have large pore-size that favours effective cell proliferation and migration.

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