Surface Modification of PHBV Scaffolds via UV Polymerization to Improve Hydrophilicity

Surface modification of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) scaffolds with polyacrylamide was achieved with the aim to improve their hydrophilicity. PHBV scaffolds were prepared using the particle-leaching technique, with a porogen size of 100-200, 200-300, 300-400 and 400-500 mum, respectively. After UV polymerization, the modified PHBV scaffolds had interconnected pores with flaky substances partially filled inside. They had a lower porosity, ranging from 80.3 to 86.6%, and higher density, 0.22-0.25 g/cm(3), than the PHBV scaffolds. Mercury intrusion porosimetry results showed that the pore sizes at the peak volume increased with the increase of porogen sizes for the modified scaffolds. No extensive weight loss of the PHBV was found after 360 days incubation in PBS at 37 degrees C. However, the weight loss of the modified PHBV increased with time before 90 days incubation. After that period, it ranged only between 5 and 7.5%, with the maximum value at 240 days. During 360 days incubation, the pH value of degradation fluid fluctuated between 7.1 and 7.2. Sheep chondrocytes were cultured on the PHBV and modified PHBV scaffolds. Results showed that the modified PHBV scaffolds provided a better surface for chondrocyte adhesion and spread.