In vitro degradation of porous degradable and bioactive PHBV/wollastonite composite scaffolds

In vitro degradation of three-dimensional composite scaffolds made from poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and wollastonite has been investigated up to 15 weeks in phosphate buffered saline (PBS) solution at 37 °C. Weight loss, water absorption, pH of the PBS and molecular weight measurements were used to monitor the degradation of the scaffolds. The results showed that the addition of wollastonite into PHBV scaffolds resulted in an increase of the water absorption and weight loss as compared to that of the pure PHBV scaffolds. However, the polymer molecular weight in the pure PHBV scaffolds was found to decrease more rapidly than that of the PHBV in the composite scaffolds. This delayed degradation in the composite scaffolds was caused probably by the dissolution of alkaline ions from the wollastonite, which resulted in a buffering effect to the acidification of the PBS due to the acid degradation products of PHBV. These results suggested that the addition of wollastonite into polymer might be a useful method to adjust the degradation rate of the composite scaffolds for special applications in tissue engineering.