Water-soluble thermosensitive chitosan copolymers were prepared by coupling Pluronic (R) onto chitosan using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as coupling agents. The physicochemical properties of the resulting copolymers were characterized and they formed thermally reversible hydrogels, which exhibit a lower critical solution temperature (LCST) at 34 degrees C in aqueous solutions. As a result, chitosan copolymers attest to the usefulness as an injectable material for cell and drug delivery because of their thermally reversible property. (c) 2005 Elsevier B.V. All rights reserved.