Effects of surface properties of bacterial poly(3-hydroxybutyrate- co -3-hydroxyvalerate) on adhesion and proliferation of mouse fibroblasts

Adhesion and proliferation of NIH/3T3 mouse fibroblasts on the surfaces of bacterial copolymer poly(3-hydroxybutyrate- co -3-hydroxyvalerate) and its mixture with poly(ethylene glycol) with differing crystallinity, surface energy, and mean roughness was investigated. The surface mean roughness of all films on both sides, at the air interface and at the glass interface, measured by atomic force microscopy, was higher (from 17.0±1.4 nm to 290.8±7.0 nm) than that of the tissue culture polystyrene control (9.5±0.6 nm). The structure, surface energy, and chemical composition of bacterial films were studied by differential scanning calorimetry, contact angle measurements, and Fourier transform infrared (FTIR) spectroscopy. After 48 h, cell proliferation on all surfaces was significantly less than on the control substrate; however, after 72 and 96 h, cell proliferation was comparable with control on some surfaces with sufficient roughness. Addition of poly(ethylene glycol) resulted in an increase of adhesion and the metabolic activity of the cells, even for relatively smooth surfaces. The complex correlation of cell metabolic activity with surface energy and crystallinity for “rough” (mean roughness >100 nm) and “smooth” (mean roughness < 100 nm) surfaces is discussed.