An asymmetrically porous nerve guide conduit (NGC) with selective permeability and hydrophilicity was prepared by rolling an asymmetrically porous poly(dioxanone-b-caprolactone) (PDOCL)/Pluronic F127 membrane fabricated by a novel immersion precipitation method. The asymmetrically porous PDOCL/Pluronic F127membrane was fabricated by immersing the PDOCL/Pluronic F127 solution (in tetraglycol) in a mold into water.
The PDOCL/Pluronic F127 mixture was precipitated in water by the diffusion of water into PDOCL/Pluronic F127mixture solution. The prepared PDOCL/F127 NGC had an asymmetric column-shape pore structure. The inner surface of the tube had sub-micron pores (< 1 μm) that can prevent fibrous tissue infiltration but permeate nutrients/oxygen, and the outer surface had micron pores (~ 200 μm) that can allow vascular ingrowth for the effective supply of nutrients and oxygen into the NGC to promote nerve regeneration. The PDOCL/F127 NGC with 3 wt% Pluronic F127 appeared to be optimal for its mechanical properties and hydrophilicity. To stimulate nerve regeneration, NGF was immobilized onto the pore surfaces of the NGC via heparin binding. The NGF immobilized on the heparinbound NGC was released in a sustained manner for up to 35 days. The NGF-immobilized asymmetrically porous PDOCL/F127 (3 wt%) NGC may be a good candidate as a NGC for enhanced nerve regeneration.