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®(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^-9 to 9.3 x 10^-11 cm²/sec. Results from the NGF release assay illustrated the presence of bioactive NGF.