Electrospinning has received increasing interest and attention in recent years for fabricating micro/nanofibers of various materials; this is due to its versatility and capability of multiple field applications, including filtration, biosensors, tissue engineering, wound dressings, drug delivery, and composites. Nonetheless, the optimization of the electrospinning process is based on a time-consuming trial-and-error procedure. An empirical study, in conformity with the Taguchi orthogonal matrix design, was carried out to investigate the influence of various processing variables on the electrospinning of resorbable poly(D,L)-lactide-co-glycolide (PLGA). Three different solvents, hexafluoro-2-propanol (HFIP), dichloromethane (DCM), and trichloromethane (TCM), were employed. Five variables were selected for evaluation, including PLGA concentration, the solution’s flow rate from the nozzle, the distance between the nozzle and ground collection, the voltage, and the type of solvents. After electrospinning, we performed a morphological analysis of nanofibers by scanning electron microscopy (SEM) and measured the fiber size by the evaluation of SEM images. Among the variables selected, the type of solvent and the applied voltage were found to be the principal variables influencing the diameter distribution of electrospun PLGA fibers. Nanofibers with the smallest fiber size (466.25±158.38 nm) could be obtained with HFIP solvent and an applied voltage of 15 kV.

Stent implantation impairs local endothelial function and may be associated with subsequent adverse cardiovascular events. Telmisartan, an angiotensin II receptor blocker that has unique peroxisome proliferator-activated-receptor-gamma-mediated effects on cardiovascular disease, has been shown to enhance endothelial function and limit neointimal hyperplasia. This study utilized hybrid biodegradable/stent nanofibers to facilitate sustained and local delivery of telmisartan to injured arterial vessels. Telmisartan and poly(d,l)-lactide-co-glycolide (PLGA) (75:25) were dissolved in hexafluoroisopropyl alcohol and electrospun into biodegradable nanofibrous tubes which were coated onto metal stents. By releasing 20% of the loaded telmisartan in 30 days, these hybrid biodegradable/stent telmisartan-loaded nanofibers increased the migration of endothelial progenitor cells in vitro, promoted endothelialization, and reduced intimal hyperplasia. As such, this work provides insights into the use of PLGA nanofibers for treating patients with an increased risk of stent restenosis.

Co-axial electrospraying is a simple and versatile process, achieving liquid atomization through electrical forces, to produce core–shell-structured nano/microparticles. Despite its advantages in terms of preparing particles with sizes ranging from 300–500 µm down to 50–70 nm, the optimization of the co-axial electrospraying process remains a challenge. In this study, we investigated experimentally the effects of processing parameters on the size distribution of co-axially electroprayed poly(d,l-lactide-co-glycolide) (PLGA) microparticles. The effects of various parameters, including voltage, flow rate ratio, travel distance, and polymeric concentration, were examined using a factorial experimental design. It was found that the particle size of electrosprayed core–shell microparticles decreases with the voltage and travel distance, and it increases with the flow rate of the solutions and the PLGA concentration in the solutions. Furthermore, to verify the existence of proteins in the co-axially electrosprayed microparticles, PLGA was used as the shell, and recombinant enhanced green fluorescent protein (reGFP) was employed as the core material. Transmission electron microscopy (TEM) and laser scanning confocal microscopy (LSCM) were employed to confirm the core–shell structure of the microparticles. The experimental results demonstrated that under optimum conditions, core–shell-structured microparticles can be successfully prepared using a protein with high activity at the core.