PLLA Membrane with Embedded Hydroxyapatite Patterns for Improved Bioactivity and Efficient Delivery of Growth Factor.

Poly(l-lactic) acid (PLLA) is widely used in guided bone regeneration membranes due to its mechanical properties and biodegradability. However, the lack of biocompatibility is a serious disadvantage. Herein, the biocompatibility of PLLA is improved by patterning hydroxyapatite (HA) loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2) under it. The HA is obtained by preparing a magnesium pattern via photolithography and hydrothermal converting. After loading rhBMP-2, the pattern is transferred to PLLA. The pattern is tightly embedded in the PLLA and retained its original position after mechanical stimuli. Fluorescence images allow to assess the protein adsorption and gradual release in a controlled manner. The amount of released rhBMP-2 is overwhelmingly large when loaded under HA because of its large surface area. Osteogenic differentiation supports the synergistic effect of HA and rhBMP-2 to improve the biocompatibility. Moreover, in vivo experiments demonstrate that the synergistic effect positively affects the healing rate of bone.