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Colloids and Surfaces B: Biointerfaces 66 (2008) 218–225 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces j o u rn al h omepage: www.elsevi er.c om /locate/c olsurfb Chitosan modified poly(l-lactide) microspheres as cell microcarriers for cartilage tissue engineering Lihong Lao, Huaping Tan, Yingjun Wang, Changyou Gao ∗ Key Laboratory of Macromolecular Synthesis and Functionalization, Ministry of Education, and Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China a r t i c l e i n f o a b s t r a c t Article history: The surfaces of poly(l-lactide) (PLLA) microspheres were modified by chitosan via a method of hydrol- Received 1 October 2007 ysis and grafting-coating to improve their compatibility to chondrocytes. The PLLA microspheres with a Received in revised form 6 January 2008 diameter of 74–150 m were fabricated by an oil/water emulsion solvent evaporation method, followed Accepted 20 June 2008 by hydrolysis in alkaline solution to produce a larger number of carboxyl groups. Using water-soluble Available online 3 July 2008 carbodiimide as a coupling reagent, chitosan was covalently grafted onto the microspheres. Due to the physical entanglement and insolubility at neutral pH, unbonded chitosan molecules were stably remained Keywords: to yield a large amount of coated chitosan. Biological performance of the control PLLA and the chito