Fabrication and characterization of permeable degradable poly(DL-lactide-co-glycolide) (PLGA) hollow fiber phase inversion membranes for use as nerve tract guidance channels

Biodegradable permeable poly(DL-lactide-co-glycolide) (PLGA) hollow fiber membranes (HFMs) were fabricated using a wet phase inversion technique. By varying several parameters, such as the spinneret size, solvent and non-solvent pair, polymer concentration, flow rate, precipitation method, drop height, and small molecular pore-forming agents, PLGA HFMs with variable sizes, surface morphologies, porosities, and diffusive permeability were obtained. Under simulated physiological conditions in vitro, PLGA HFMs exhibited a degradation profile to accommodate nervous system regeneration and axonal outgrowth. While accelerated degradation resulted in substantial molecular weight loss starting at 2 weeks and loss of selective permeability at 3 weeks. PLGA HFMs maintained gross structural integrity in the first 4 weeks, followed by sharp weight loss at 6 weeks and complete disappearance at about 8 weeks. When compared to the raw PLGA material in a pellet form, which underwent heterogeneous degradation, the PLGA HFMs exhibited a homogeneous degradation where the surface and bulk degraded at approximately the same rate, and an overall lower degradation rate. Our results indicate that using a wet phase inversion technique, degradable HFMs with variable size, inner and outer surface morphologies, porosity, and permeability with potential applications for nerve tract guidance conduits can be fabricated. (c) 2006 Elsevier Ltd. All rights reserved.