Effects of Physico-Chemical Treatments on PLGA 50:50 Electrospun Nanofibers

Biocompatible polymers are used as scaffolds to mimic the native extracellular matrix (ECM) in tissue engi-neering applications. However, when integrated into microengineered cell and tissue cultures, such scaffolds are often subjected to several alterations in the chemical milieu for drug testing purposes, modelling a disease, etc. Changes in the chemical environment may affect the architecture and function of the engineered scaffolds; therefore, it is important to study the material and structural changes that can occur in the scaffolds and the stimuli that bring about those changes. Nanofiber membranes of poly(D, L-lactic -co-glycolic acid) (PLGA) (Lactic acid Glycolic acid 50/50) were subjected to thermal treatments in air and thermo-chemical treatments in deionized water, ethanol and 2-Propanol at various temperatures to study structural changes due to swelling. The effects of the physico-chemical treatments on the nanofiber films were quantified by studying the average fiber diameter and porosity. Physico-chemical treatments led to the creation of interfiber bonds in the nanofibers. Interfiber bonds are believed to be formed by the fusion of mobile macromolecular polymer chains in the fibers due to increased Brownian motion. Rates of increase of average fiber diameter were 6.6 +/- 1.2 to 26 +/- 10 times faster in thermochemical treatments than in air at 50 degrees C. This is believed to be caused by a coupled thermo-chemical effect due to physico-chemical interactions between the reagent molecules and the nanofibers. Glass -transition temperatures of the nanofiber films showed a 23.5 +/- 1.8% decrease due to solvation in water and a 12.6 +/- 3.7% increase due to solvation in ethanol at room temperature, respectively. Simple physico-chemical treatments like heat and solvation have been shown to change the structural (fiber diameter, porosity) and material (thermal) properties of PLGA nanofiber scaffolds. Such changes are important to study and characterize, especially for biomedical applications of nanofiber scaffolds.