In this studs,, we analyzed the physicochemical and biophysical properties of three-dimensional scaffolds modified using polyethyleneimine (PEI) and applied these scaffolds to the cultivation of bovine knee chondrocytes (BKCs). PEI was crosslinked in the bulk or oil the surface of the ternary scaffolds comprising polyethylene oxide, chitin and chitosan. The results revealed that when the concentration of PEI was less than 300 mu g/mL, the cytotoxicity of a scaffold was on the same order in the two method of modification. All increase in the concentration of PEI favored the adhesion of BKCs. When the amount of PEI in scaffolds is fixed, the surface-modified scaffolds exhibited a higher adhesion efficiency of BKCs than the bulk-modified scaffolds. For the regeneration of cartilaginous components, a higher amount of PEI in a scaffold yielded larger amounts of proliferated BKCs, secreted glycosaminoglycans, and produced collagen. Ill addition, the formation of neocartilage in the surface-modified scaffolds was more effective that? that in the bulk-modified scaffolds. These tissue-engineered scaffolds, modified by all appropriate concentration of PEI, call be potentially applied to cartilage repair in clinical trials. (C) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 25: 1459-1467, 2009