Chitosan-based injectable and thermosensitive hydrogel

The chitosan(CS)-based injectable and thermosensitive hydrogels are injectable liquid at low temperature and transform to semisolid hydrogels at body temperature. The formation of hydrogels is mainly due to the physical interactions such as hydrogen bonding, electrostatic interactions and hydrophobic interaction. Therefore I the thermosensitive hydrogels don't require organic solvents, copolymerization agents, or an externally applied trigger for gelation, especially suitable for biomaterial applications. The CS/polyol salt combinations were firstly developed to produce thermosensitive neutral hydrogels. Many modified CS polymers, such as the PEG-grafted CS, N-isopropylacrylamide- grafted CS, Pluronic((R)) -grafted CS, hydroxybutyl CS and quatenized CS, also have thermosensitive characteristics. In this paper, the structure and properties of the chitosan-based thermosensitive hydrogels are simply introduced. and their applications in the field of drug delivery and tissue engineering are reviewed in detail.