Improving cell affinity of poly (D,L-lactide) film modified by anhydrous ammonia plasma treatment

Anhydrous ammonia gaseous plasma treatment was used for improving cell affinity of the poly(D,L-lactide) film surface. The contact angle was measured and the surface energy was calculated through harmonic mean equations. The surface chemical composition of the sample was identified by X-ray photoelectron spectroscopy (XPS) analysis. It was demonstrated that the O-containing and N-containing groups such as hydroxyl and amine were incorporated onto the surface of films. The effect of preserving methods for maintaining the hydrophilicity was also investigated. The result indicated that preserving at low temperature (0-4°C) was sufficient to maintain the improvements. It could resolve the problem of hydrophilicity being partially lost with preserving time after plasma treatment. Mouse 3T3 fibroblast cells were used as model cells to compare the cell affinity of the modified films and control. The ammonia plasma treatment could promote the cells attachment and cells growth. After 4 days culture, the plasma treated films yielded almost two magnitude cells compared with the control.