Effect of biological/physical stimulation on guided bone regeneration through asymmetrically porous membrane

Asymmetrically porous polycaprolactone (PCL)/Pluronic F127 guided bone regeneration (GBR) membranes were fabricated. The top surface of the membrane had nanosize pores (∼10 nm) which can effectively prevent invasion by fibrous connective tissue but permeate nutrients, whereas the bottom surface had microsize pores (∼200 μm) which can enhance the adhesiveness with bone tissue. Ultrasound was applied to a bone morphogenetic protein (BMP‐2)‐immobilized PCL/F127 GBR membrane to investigate the feasibility of using dual biological (BMP‐2) and physical (ultrasound) stimulation for enhancing bone regeneration through the membrane. In an animal study using SD rats (cranial defect model), the bone regeneration behavior that occurred when using BMP‐2‐loaded GBR membranes with ultrasound treatment (GBR/BMP‐2/US) was much faster than when the same GBR membrane was used without the ultrasound treatment (GBR/BMP‐2), as well as when GBR membranes were used without stimulations (GBR). The enhanced bone regeneration of the GBR/BMP‐2/US group can be interpreted as resulting from the synergistic or additive effect of the asymmetrically porous PCL/F127 membrane with unique properties (selective permeability, hydrophilicity, and osteoconductivity) and the stimulatory effects of BMP‐2 and ultrasound (osteoinductivity). The asymmetrically porous GBR membrane with dual BMP‐2 and ultrasound stimulation may be promising for the clinical treatment of delayed and insufficient bone healing. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.