Surface engineering of poly(D,L-lactic acid) by entrapment of chitosan-based derivatives for the promotion of chondrogenesis.

Chitosan and chitosan-amino acid derivatives were explored to engineer poly(D,L-lactic acid) (PDL-LA) as an extracellular matrix-like surface to promote cell adhesion and growth. Four kinds of chitosan-amino acid derivatives were prepared to mimic the carbohydrate moieties of cell matrix glycoprotein. The chitosan-amino acid derivatives were characterized by using Fourier transform infrared and ultraviolet spectra. The amino acid content on chitosan-amino acid derivatives was determined by using a ninhydrin-ultraviolet method. A new strategy, entrapment, was therefore used to modify the PDL-LA membrane with chitosan and chitosan-amino acid derivatives. The results of X-ray photoelectron spectroscopy, attenuated total reflectance-Fourier transform infrared, and contact angle confirmed that a stable thin film of chitosan and its derivatives can be entrapped on the surface of the PDL-LA membrane. From the results of chondrocyte cytocompatibility, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assays, and cell morphology, the chitosan-amino acid derivative modified PDL-LA membranes were shown to promote chondrogenesis. The novel surface treatment method combines the good mechanical property of PDL-LA with the good cytocompatibility of chitosan derivatives, which may have potential for tissue engineering.