Date of Award
Doctor of Philosophy
Dr. Wankei Wan
Dr. Martin Zinke-Allmang
Poly(vinyl alcohol) (PVA) is a well known biocompatible synthetic polymer. PVA is not cell compatible due to its high hydrophilicity. As prepared by electrospinning in the form of nanofibers, it is unstable in aqueous environments including cell culture media. For tissue regeneration applications, this study demonstrates the use of PVA scaffold utilizing electrospun nanofibers with aqueous stability and cell compatibility toward creating biomaterial-tissue hybrid based medical devices. Two different approaches: heat treatment and ion beam treatment were developed to improve aqueous stability and promote cell compatibility for PVA fibers. Using a thermal annealing method at elevated temperatures, the fibers became stable in water. This observation correlated closely to the change in the crystallinity of PVA. Elastic moduli of individual fibers were determined using a multi-points bending approach by atomic force microscopy. Elastic moduli of as-spun PVA fibers were determined to be a function of fiber diameter and humidity. Significant changes in the elastic modulus of the modified PVA fibers were also observed. To improve the cell compatibility, low energy N+ and He+ ion beams were used to introduce amine and carbonyl functional groups. Cell compatibility was assessed in vitro using primary human skin fibroblasts (hsF). Confocal microscopy confirmed the adhesion and proliferation of hsF on both the random and aligned PVA fibers after the ion beam treatment, while cells failed to adhere to the untreated fibers. Cell morphology was observed to align and elongate along the fiber axis on aligned PVA fibers. After 10 days of proliferation, cells were found to form confluent layers and even multiple layers on the N+treated fibers. Cell proliferation depends on ion species, ion dose and fiber alignment. With the two post-processing treatments, PVA fibrous scaffold showed the potential to become biomaterial-tissue hybrid based medical devices for tissue regeneration applications.
Wong, Kenneth K.H., "Cell Compatible Electrospun Poly(vinyl alcohol) Fibers for Tissue Regeneration" (2010). Digitized Theses. 3701.