Developing A Synthetic Composite Membrane For Cleft Palate Repair.

An oronasal fistula is a passage between the oral and nasal cavity. Currently, surgical procedures use mucosal flaps or collagen grafts to make a barrier between oral and nasal cavities. Our aim was to develop a cell-free synthetic repair material for closure of nasal fistulas. We surface functionalized electrospun polyurethane (PU) and poly-L-lactic acid (PLLA) and composite polymer (PU-PLLA) membranes with acrylic acid through plasma polymerization. Membranes were treated in a layer-by-layer approach to develop highly charged electrostatic layer which could bind heparin as a pro-angiogenic glycosaminoglycan. The properties were evaluated through physical, chemical and mechanical characterization techniques. Cytotoxicity was tested with MC3T3 pre-osteoblast cell lines for 3, 7 and 14 days and vasculogenesis was assessed by implantation into the chorio-allantoic membrane in chick embryos for 7 days. In vivo biocompatibility was assessed by subcutaneous implantation in rats for 1, 3 and 6 weeks. The membranes consisted of random fibres of PLLA-PU with fibre diameters of 0.47μm and 0.12μm respectively. Significantly higher cell proliferation and migration of MC3T3 cells at 3, 7 and 14 days were shown on plasma coated membranes compared to uncoated membranes. Further, it was found that plasma coated membranes were more angiogenic than controls. In vivo implantation of membranes in rats did not reveal any gross toxicity to the materials and wound healing was comparable to the native tissue repair (sham group). We therefore present a plasma functionalized electrospun composite polymer membrane for use in the treatment of fistulas. These membranes are flexible, non-cytotoxic and angiogenic and we hope should lead to permanent closure of oronasal fistula.