Preparation and characterization of chitosan/poly(vinyl alcohol) chemically crosslinked blends for biomedical applications

In this study the development and characterization of novel polymer blends based on chitosan and poly(vinyl alcohol) and chemically crosslinked by glutaraldehyde for possible use in a variety of biomedical applications is reported. Mechanical properties of hybrids were evaluated by stress–strain tensile tests. Also, the microstructure, morphology and crystallinity of the blended hydrogels were characterized through X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy analysis. Moreover, biocompatibility, cytotoxicity and cell viability were also performed by swelling test in simulated body fluid, MTT assay with cell culture. The relative crystallinity of pure chitosan film was reduced from approximately 23% to 18% when the polymeric network was reticulated by glutaraldehyde. A similar trend was also observed for PVA films. It was found that by increasing the chitosan content relative to PVA the swelling index of the blend has decreased from about 200% (pure PVA) to approximately 80% (50/50 chitosan/PVA), reflecting the reduction in the mobility of the polymer network and the hydrophilic behavior of the blend. The mechanical properties of the polymers were also significantly altered by changing blend composition and chemical crosslinking. Chitosan films have shown values of 50 MPa and 45% for maximum tensile strength and tensile elongation, respectively. It was verified that the average blend toughness has decreased about 40% by increasing the chitosan concentration from 25% (14.8 MJ/m3) to 50% (8.9 MJ/m3) related to a brittle characteristic of chitosan. In addition, the obtained results of elastic moduli were 0.1 GPa for PVA and 0.8 GPa for chitosan. The tested hydrogels clearly show adequate cell viability, non-toxicity and suitable mechanical properties which can be tailored to for potential use in skin engineering applications.