Guidance channel development: controlled release of NGF from PLGA scaffolds

Three categories of stimuli have demonstrated influential effects on neural regeneration: physical, electrical and chemical. Current research is underway to optimize each of these stimuli in a nerve guidance channel in order to achieve neural regeneration at the site of an injured nerve. This project focused on the delivery of nerve growth factor (NGF) from poly(lactic-co-glycolic acid) (PLGA) scaffolds for use in development of nerve guidance channels. More specifically, the main objectives were to fabricate a delivery system to analyze the release of a model protein (ovalbumin) and NGF in an aqueous environment and mathematically model this delivery. Protein-loaded PLGA scaffolds were fabricated by standard dissolution-evaporation techniques with the inclusion of poly(ethylene glycol) (PEG)(MW 8 kDa). Aqueous release profiles of OVA and NGF were determined over a 4-week period through various assay techniques. A MATLAB/spl reg/(The Mathworks, Inc) program was written to determine the unknown effective diffusion coefficient for the each set of collected data based on an equation derived from Fick's second law. The calculated effective diffusion coefficients for OVA ranged from 7.0 x 10/sup -9/ to 9.3 x 10/sup -11/ cm/sup 2//sec. Results from the NGF release assay illustrated the presence of bioactive NGF.