Graft copolymerization of methyl methacrylate onto mercaptochitin and some properties of the resulting hybrid materials

Chitin and its derivatives: Structural properties and biomedical applications

Chitin, a polysaccharide that occurs abundantly in nature after cellulose, has attracted the interest of the scientific community due to its plenty of availability and low cost. Mostly, it is derived from the exoskeleton of insects and marine crustaceans. Often, it is insoluble in common solvents that limit its applications but its deacetylated product, named chitosan is found to be soluble in protonated aqueous medium and used widely in various biomedical fields. Indeed, the existence of the primary amino group on the backbone of chitosan provides it an important feature to modify it chemically into other derivatives easily. In the present review, we present the structural properties of chitin, and its derivatives and highlighted their biomedical implications including, tissue engineering, drug delivery, diagnosis, molecular imaging, antimicrobial activity, and wound healing. We further discussed the limitations and prospects of this versatile natural polysaccharide.

Chitosan-based nanomaterials: a state-of-the-art review

This manuscript briefly reviews the extensive research as well as new developments on chitosan based nanomaterials for various applications. Chitosan is a biocompatible and biodegradable polymer having immense structural possibilities for chemical and mechanical modification to generate novel properties and functions in different fields especially in the biomedical field. Over the last era, research in functional biomaterials such as chitosan has led to the development of new drug delivery system and superior regenerative medicine, currently one of the most quickly growing fields in the area of health science. Chitosan is known as a biomaterial due to its biocompatibility, biodegradability, and non-toxic properties. These properties clearly point out that chitosan has greater potential for future development in different fields of science namely drug delivery, gene delivery, cell imaging, sensors and also in the treatment as well as diagnosis of some diseases like cancer. Chitosan based nanomaterials have superior physical and chemical properties such as high surface area, porosity, tensile strength, conductivity, photo-luminescent as well as increased mechanical properties as comparison to pure chitosan. This review highlights the recent research on different aspect of chitosan based nanomaterials, including their preparation and application.

Regioselective Grafting of Poly(ethylene glycol) onto Chitosan and the Properties of the Resulting Copolymers

PEG was grafted onto chitosan regioselectively at the hydroxyl groups with phthaloylchitosan as an intermediate. After the graft reaction, the phthaloyl groups were deprotected to give chitosan-g-PEG copolymers with free amino groups. The chemical structure of the graft copolymers was confirmed by FT-IR, (1)H and (13)C NMR spectroscopy. The resulting graft copolymers showed improved thermal stability compared to the original chitosan, and showed a lower thermal transition temperature at around 185 degrees C. Chitosan-g-PEG exhibited a high affinity not only for aqueous acid but also for some organic solvents because of the presence of abundant free amino groups and PEG branches, and it exhibited higher hygroscopicity and moisture retention ability than chitosan. [structure: see text]