In situ preparation of poly(l-lactic acid-co-glycolic acid)/hydroxyapatite composites as artificial bone materials

Abstract

Poly(l-lactic acid-co-glycolic acid)/hydroxyapatite (PLGA/HAp) composites were fabricated by the in situ polymerization of l-lactide and glycolide in porous HAp disks, using lipase MM, derived from Mucor miehei, as a catalyst. Various PLGA/HAp composites were obtained by changing the feed ratio of l-lactide and glycolide. The fourier transform infrared spectroscopy, scanning electron microscopy and porosity measurements showed that the porous HAp was completely filled with PLGA after polymerization at 100 °C for 9 days. Lactyl unit fractions (F L) of obtained PLGA calculated from the 1 H nuclear magnetic resonance were consistent with the feed fraction of l-lactide (f L). The PGA/HAp, PLGA20/HAp, PLGA50/HAp, PLGA80/HAp and PLLA/HAp composites showed maximum bending strengths of 91.1 MPa, 78.8 MPa, 73.4 MPa, 54.3 MPa and 67.0 MPa, respectively. These values were 4.7-2.8 times greater than that of the untreated porous HAp disks and were suitable for artificial bone materials. The cell adhesion and proliferation properties of these materials with osteoblast-like MC3T3-E1 cells suggest that these PLGA/HAp composites have suitably bioactive surfaces. The PLGA/HAp composites showed higher alkaline phosphatase activity after cultivation of rat bone marrow stromal cells.