Increased response of Vero cells to PHBV matrices treated by plasma

The copolymers poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) are being intensely studied as a tissue engineering substrate. It is known that poly 3-hydroxybutyric acids (PHBs) and their copolymers are quite hydrophobic polyesters. Plasma-surface modification is an effective and economical surface treatment technique for many materials and of growing interest in biomedical engineering. In this study we investigate the advantages of oxygen and nitrogen plasma treatment to modify the PHBV surface to enable the acceleration of Vero cell adhesion and proliferation. PHBV was dissolved in methylene chloride at room temperature. The PHBV membranes were modified by oxygen or nitrogen-plasma treatments using a plasma generator. The membranes were sterilized by UV irradiation for 30 min and placed in 96-well plates. Vero cells were seeded onto the membranes and their proliferation onto the matrices was also determined by cytotoxicity and cell adhesion assay. After 2, 24, 48 and 120 h of incubation, growth of fibroblasts on matrices was observed by scanning electron microscopy (SEM). The analyses of the membranes indicated that the plasma treatment decreased the contact angle and increased the surface roughness; it also changed surface morphology, and consequently, enhanced the hydrophilic behavior of PHBV polymers. SEM analysis of Vero cells adhered to PHBV treated by plasma showed that the modified surface had allowed better cell attachment, spreading and growth than the untreated membrane. This combination of surface treatment and polymer chemistry is a valuable guide to prepare an appropriate surface for tissue engineering application.