Electro-Spinning and Electro-Blowing of Hyaluronic Acid

TLDR

The study aimed to fabricate nonwoven hyaluronic acid nanofibrous membranes by electro‑spinning and electro‑blowing, and to investigate processing parameters that influence membrane morphology. Electro‑spinning and electro‑blowing were performed while varying HA concentration, solution viscosity, ethanol addition, feeding rate, and air flow temperature and rate, with rheology and SEM used to assess morphology. Optimal HA concentration (1.3–1.5 w/v %) yielded nanofibers, but consistent high‑quality membranes required electro‑blowing at 57 °C with a 70 ft³ hr⁻¹ flow, producing uniform nanofibers and a high‑quality nonwoven membrane.

Abstract

In this study, hyaluronic acid (HA) was electro-spun and electro-blown to prepare nonwoven nanofibrous membranes. Critical parameters for processing and corresponding effects on the membrane morphology were investigated using the methods of rheology and scanning electron microscopy (SEM). During electro-spinning, the optimal HA concentration window for nanofibrous formation was determined within a narrow range of 1.3−1.5 w/v %, corresponding to a solution viscosity range of 3−30 Pa s at a shear rate of 1 s-1. SEM results indicated that, with increases in (1) the total concentration by blending of low molecular weight HA, (2) the evaporation rate by the addition of ethanol, and/or (3) the feeding rate of solution, the electro-spinning performance for creating nanofibers was improved. However, the improvement was not sufficient to achieve a consistent production of high quality nonwoven nanofiber membranes. This problem was overcome by a new electro-blowing process using the combination of air flow and electro-spinning. Although air blowing at room temperature around the spinneret orifice did not exhibit a remarkable enhancement of nanofiber formation of HA, the performance was significantly improved with an increase in the air blowing rate. SEM results showed that the temperature of air-blowing was the most effective parameter in ensuring HA nanofiber formation. As the temperature of the blown air increased from 25 to 57 °C, the nanofiber formation became consistent and uniform. A high quality HA nonwoven membrane of nanofibers was successfully produced by blowing air at 57 °C with a 70 ft3/hr flow rate.