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Skin loss is one of the oldest and still not totally resolved problems in the medical field. Since spontaneous healing of the dermal defects would not occur, the regeneration of full thickness of skin requires skin substitutes. Tissue engineering constructs would provide a three dimensional matrix for the reconstruction of skin tissue and the repair of damage. The aim of the present work is to develop a chitin based scaffold, by blending it with poly(butylene succinate) (PBS), an aliphatic, biodegradable and biocompatible synthetic polymer with excellent mechanical properties. The presence of chondroitin sulfate nanoparticles (CSnp) in the scaffold would favor cell adhesion. A chitin/PBS/CSnp composite hydrogel scaffold was developed and characterized by SEM (Scanning Electron Microscope), FTIR (Fourier Transform Infrared Spectroscopy), and swelling ratio of scaffolds were analyzed. The scaffolds were evaluated for the suitability for skin tissue engineering application by cytotoxicity, cell attachment, and cell proliferation studies using human dermal fibroblasts (HDF). The cytotoxicity and cell proliferation studies using HDF confirm the suitability of the scaffold for skin regeneration. In short, these results show OPEN ACCESSPolymers 2014, 6 2975 promising applicability of the developed chitin/PBS/CSnps ternary composite hydrogel scaffolds for skin tissue regeneration.

Gelatin (Gel) and chitosan (CTS) have several biomedical applications because of their biodegradability and biocompatibility. Crosslinking of Gel and Gel/CTS systems was evaluated using N-acetyl-D-glucosamine (GlcNAc) formed into sponges by lyophilization. The prepared sponges were used to study the adsorption and desorption of fluorescein isothiocyanate (FITC) labeled bovine serum albumin (BSA) as a model instead of a growth factor. The effect of FITC-BSA concentration and temperature on the adsorption behavior of Gel/CTS sponges was investigated. The Langmuir adsorption isotherm model was used on the basis of the assumption that monolayer adsorption occurs on the surface; the results fit with the experiment data. The adsorption constants were 5.77 and 9.68 mL/mg for Gel and Gel/CTS sponges, respectively. The adsorption thermodynamic constants were found; adsorption onto sponges was an exothermic reaction. In particular, Gibbs free energy (ΔG) exhibited negative values in the range of 283-343 K for both Gel and Gel/CTS sponges, demonstrating the spontaneous nature of adsorption reaction. In addition, desorption behavior was evaluated for different concentrations and pH values of the FITC-BSA solution. The high adsorbed amounts of FITC-BSA on sponge resulted in high desorbed amounts in sponge, up to 55% from 3.5 mg/mL adsorbed concentration (around 1.5 mg from 3 mg adsorb amount). Desorption decreased following the buffer solution pH decrease, from 7.4 to 4 and 2 in Gel and Gel/CTS sponges, respectively. Based on the results of this preliminary study, these composite sponges could have significant application in biomedical materials.

Gelatin fibers have been prepared by dry spinning based on the sol-gel transition phenomena of aqueous gelatin solutions. This method is simple and environmentally friendly because only water is used for the spinning, thereby avoiding the use of any toxic organic solvents. A sol-state aqueous solution of gelatin at 50˝C was extruded into air through a thin nozzle at room temperature followed by high-speed stretching in air. As a result, a stretched and shiny gelatin fiber was produced. To improve the mechanical and water-resistant properties of the fibers, a crosslinking treatment by the addition of sugars, denacol, and glutaraldehyde vapor was used. Despite their smooth surfaces, the gelatin fibers exhibited a multi-porous phase on the inside, probably owing to the retention of water during the spinning process. The mean diameters of the obtained fibers with all crosslinking agents were approximately 50-60 µm. Furthermore, the mean tensile strength was increased by all crosslinking agents. In particular, the use of N-acetyl-D-glucosamine and glutaraldehyde as the crosslinkers resulted in a remarkable increase in tensile strength and water resistance. Moreover, their properties were further improved after heat treatment. These fibers also exhibited good water resistance and maintained their morphologies for more than 90 days.

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