Enhanced cell affinity of poly(l-lactic acid) modified by base hydrolysis: Wettability and surface roughness at nanometer scale

While biodegradable, biocompatible poly(l-lactic acid) (PLLA) is a popular material for the manufacture of tissue engineering scaffolds, its surface properties are not particularly suitable for cell growth. In the present study, poly(l-lactic acid) (PLLA) films were fabricated by a solution casting method and their surfaces were subsequently modified by NaOH hydrolysis. The changes of surface properties were characterized by contact-angle measurement and atomic force microscopy (AFM). Mouse L929 fibroblasts were used as model cells to evaluate the cell affinity of PLLA before and after surface modification. The results showed that the hydrophilicity of PLLA films was improved after treatment and the surface roughness, presented with a roughness parameter, Ra, increased from about 20nm to between 40 and 200nm. The adhesion and growth of mouse L929 fibroblasts on modified films were significantly improved. Thus, improved hydrophilicity and increased surface roughness at 40–200nm could significantly enhance cell adhesion and growth on modified PLLA that could be useful for applications in tissue engineering.