Evaluation of the biological responses of osteoblast-like UMR-106 cells to the engineered porous PHBV matrix.

Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) has been investigated for biomedical applications due to its many biologically favorable properties. However, to explore its application in bone tissue engineering, the poorly bioactive surface property of PHBV must be improved. To engineer PHBV to achieve a biologically active surface, in this study each porous PHBV matrix was prepared by solute leaching of salt/PHBV cast film and was treated with ozone followed by dip coating with type I collagen. The biological responses of osteoblast-like UMR-106 cells after being grown on the engineered PHBV matrix were evaluated. Confocal microscopy and the MTT assay were used to map and quantify the viable cell proliferation on the PHBV matrix, respectively. The cells were cultivated in osteogenic media containing beta-glycerophosphate and later stained with alizarin red to visualize mineralization of the matrix. RNA was extracted from the UMR-106 cells, and reverse transcriptase-polymerase chain reaction (RT-PCR) was applied to detect expression of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) (a house keeping gene) and bone sialoprotein (BSP) (marker of the osteoblastic phenotype). The results showed that the UMR-106 cells after cultivation on the engineered PHBV matrix retained the osteoblastic phenotype characteristics, indicating that the porous PHBV matrix after ozone treatment and collagen dip coatings are a promising scaffold for bone tissue engineering applications.