| dc.description.abstract | Bio-inspired materials offer intrinsic properties such as biodegradability and biocompatibility. These properties make these materials strong candidates for a variety of applications such as biomedical, textile, filtration, packaging and food applications. Among these materials, chitin, the second most abundant polysaccharide after cellulose, is a very attractive material. It is the main structural component of exoskeletons or the cuticles of many invertebrates and has many desirable properties. However, chitin is insoluble in most organic solvents, which limits its practical use. Our group has demonstrated a novel method of developing self-assembled ultrathin chitin nanofibers from the solution of squid pen -chitin in hexafluoroisopropanol (HFIP). Based on this method, I have developed different techniques to fabricate high quality chitin films and studied the process-structure-property relationship in these films. Based upon the knowledge I obtained from this study, I have fabricated flexible, yet sturdy micropatterned chitin substrates with desirable microstructure and mechanical properties for tissue engineering, specifically myocardial tissue engineering. These substrates show no cytotoxicity and great mechanical stability in the wet condition of cell culture. Focusing on the mechanical properties of these substrates and getting inspired by nature, I have based my next work upon enhancing these properties by mixing chitin nanofibers and silk fibroin to make chitin-silk biocomposites. The mechanical properties of these biocomposites enhances with respect to chitin and silk alone due to strong hydrogen bonding between two molecules. Based on this study, I have shown the self-assembly of chitin nanofibers in the matrix of another natural component, GelMA, a functionalized gelatin and collagen derivative. This GelMA-chitin biocomposites offer outstanding properties such as high strength and extensibility and also great biocompatibility and vasculogenic activity. In this way, throughout the course of my PhD, I have accomplished developing innovative bio-inspired nanofiber biomaterials with great biological, physical and mechanical properties to be used in biomedical applications. The outlook of my research is to replace HFIP with more green solvents preferably water systems. HFIP is a volatile corrosive liquid that can cause burns and respiratory problems in human. Using water systems to self-assemble chitin nanofibers leads to establishment of environmentally-friendly process to make nanofiber films with great strength and stiffness and high surface area using only natural green materials and processes and with causing no harmful waste. | |
