1.1.2 Chitin and Chitosan
It is the second plentiful polysaccharide associated with marine species. It is reported from the exoskeleton of Arthropoda , which includes Arachnids , Myriapods , Crustaceans(Bastiaens et al., 2019), Fungi, algae, protozoa, Onychophora ,Entroprocta (horseshoe worms), Ectoprocta (lamp shell),Bryozoa (Kaur & Dhillom, 2014), Porifera , Mollusca(Rahman & Halfar, 2014), and phylum Cnidaria (Bo et al., 2012). Chitin is acetylated polymer made by N-acetyl-d-glucosamine and chitosan is formed by chemical or enzymatic deacetylation of chitin (Verma & Fortunati, 2019). As per micro-fibril orientations of chitin, it has three different forms α-, β- and γ. Both the polymers are highly porous, biodegradable, biocompatible, structural dependable, non-toxic, chemically inert and less soluble.
Chitin and Chitosan’s physiochemical and biochemical qualities provide ease for molding it into membranes, gels, beads and nanoparticles (Ifuku et al., 2009). Both are applicable in transducer surface modifiers, biosensors, drug and gene delivery, tissue engineering, stem cell technology, surgical dressings, and scaffolds (Elieh-Ali-Komi & Michael 2016). Polymeric scaffolds of chitin and chitosan are utilized successfully for tissue repair and regeneration. Nanosilver composite scaffolds of both are used for wound healing. They have an antibacterial activity and blood clotting ability as well (Madhumathi et al., 2009).
Chitosan combines with other materials like collagen or polyvinyl alcohol and improves its strength and cell attachment potential. In addition chitosan is capable to form tough hydrogel thin film, which can be used for electrodeposition on electrode surfaces for fabrication of micro and nano biosensors. Chitosan-derived immobilized matrices on a biosensor surface have shown excellent accuracy, selectivity and reliability for the recognition of a varied range of biomolecules (Jiang & Wu, 2019). Chitosan can be applied in the diagnostic, protein attachment in biological processes and surface adaptation of cells as well