Investigation into the electrospinning of hyaluronic acid

Abstract

Electrospinning has become a popular method for the production of fibrous mats with diameters on the order of a few hundred nanometers. A simple setup has made it a versatile method for the processing of many soluble polymers into such a fibrous state. The fibers formed are capable of being chemically or physically tailored for many applications, most notably tissue engineering and filtration, due to the high surface area to volume ratio that nanofibers exhibit. The process can be adapted to large scale production, which invites much research into developing and completely understanding the process. Some have even considered the process to be an environmentally “green” method of nanomaterial production.Recently there has been much work involving the use of natural polymers, such as hyaluronic acid (HA) in the form of nanofibrous mats for the previously mentioned applications. Hyaluronic acid is a major glycosaminoglycan found in the extracellular matrix of connective tissue in higher mammals. Therefore, filtration and tissue engineering applications would greatly benefit from the use of this material, especially in nanofiber form. Although, the unique properties of these polymers, including an extremely high solution viscosity at low concentrations as well as their being polyelectrolytes, have provided for significant barriers to their electrospinnability. Currently carrier polymers, such as poly (ethylene oxide) are required in a blend to successfully produce nanofibers of HA.This work primarily focused on determining proper solvent systems that allow for the successful production of pure HA nanofibrous mats via electrospinning without the need for blending with other polymers. Specifically, the work involved using strong solvents for HA, either via basic solutions of ammonium hydroxide or aqueous solutions containing DMF and various phosphate salts to change conductivity and rheological properties and allow for successful nanofiber production. Nanofibrous mats of HA were produced in ammonium hydroxide solution as well as in water:DMF solutions containing sodium phosphate, glycerol phosphate and tripolyphosphate.%%%%M.S., Materials Science and Engineering – Drexel University, 2009