Electrospun Polymeric Micro and Nanofibers Expanded by Supercritical CO2 for Applications in The Medical Field

This study describes the production of electrospun polylactic acid (PLA) membranes followed by expansion based on supercritical technology. The influence of electrospinning process on fiber morphology and physical characteristics was analyzed. The most promising membranes, i.e., those with lowest number of defects, were subjected to expansion process using supercritical CO2 (scCO2). Membranes were characterized in terms of morphology by scanning electron microscopy and microtomography. Polymer characteristics such as thermal transitions and degree of crystallinity were evaluated by differential scanning calorimetry and X-ray diffraction. The expansion process promoted an increase in fibers diameter and in the surface area. The degree of PLA crystallinity was very low in the electrospun fibers and showed an increase in the expanded fibers. The cell viability was evaluated and showed viability above 70% being considered non-cytotoxic material. The two techniques, which are commonly used separately, resulted in a three-dimensional structure with potential application in scaffolds.