Thermally stabilised, crosslinker-free poly(vinyl alcohol) nanofibers produced by electrospinning: Applications in cell processing and tissue engineering

Abstract

Electrospun poly(vinyl alcohol) (PVA) nanofibers are used extensively in biomedical applications, but many production methods rely heavily on the use of chemical crosslinkers to stabilise the fibrous morphology against dissolution in aqueous environments. A crosslinker-free approach, based on heat treatment at 180 °C for up to 16 hours, was used to stabilise nanofibers produced by cutting edge needleless direct current (DC) and alternating current (AC) electrospinning platforms. Characterisation of these materials showed that heat treatment preserved fibre morphology and prevented their dissolution, and that neither production method nor treatment duration had a negative impact on cytocompatibility. Application of the nanofibrous membranes for cell processing in the context of blood salvage during oncological surgeries, involved challenging them with various suspensions of different cell populations (sheep’s blood, neural blastoma cells as a cancer model and human erythrocytes). The thermally stabilised PVA nanofibers allowed the unhindered passage of cells under convective flow, with the loose structure of AC spun materials giving the highest recovery. The absence of flow channelling was further confirmed using the DigiDEM computational fluid dynamics software, and some early prototype designs of a prospective housing for the above nanofibers were also explored. The final part of this study investigated the potential use of the thermally stabilised, needleless DC electrospun supports from 98% and 99% hydrolysed PVA, in tissue engineering. A battery of bio- and haemocompatibility assays indicated that the 4 hours heat treated fibrous mats resulted in optimal cell proliferation, whilst maintaining minimum levels of thermal degradation, the latter agreeing with results obtained during the cell processing work.