THE INFLUENCE OF ATMOSPHERIC PRESSURE PLASMA SURFACE-MODIFIED POLYMERS PVDF, ECTFE, AND PEEK ON PRIMARY MESENCHYMAL STEM CELL RESPONSE

摘要

The body's response to an implanted material depends upon many factors, including biological interactions at the interface of the implant and its surroundings. Selectively modifying the surface of biomaterials is a practical approach to induce a site-specific desirable biological response. The fluoropolymers, polyvinylidenedifluoride (PVDF), ethylene-chlorotrifluoroethylene (ECTFE), and engineering resin, polyetheretherketone (PEEK), are known for their chemical resistance, thermal stability, and low surface energy, a great combination for low biological activity and, thus long-term stability, but very little integration with surrounding tissue. Atmospheric pressure plasma (APP) a clinically-safe plasma method, was applied to the substrates to functionalize the plastic surfaces for a more polar and hydrophilic environment. Freshly isolated mesenchymal stem cells (MSCs) were cultured on the surfaces in order to expand on the limited knowledge of topographical effects on differentiation of stem cells. To assess the cellular activity on each surface, modified and unmodified, biological assays were performed to understand cellular morphology, cytoskeletal structure, viability, and differentiation. Surface energy calculations via contact angle measurements showed a significant increase after plasma-treatment on each material. Crystal violet assay indicated an increase in cell viability from APP compared to unmodified surfaces. Visualization of nuclei and α-tubulin via immunofluorescence indicated greater cellular activity from APP treatment. Scanning electron microscopy (SEM) imaging showed spherically-shaped MSCs had greater activity and attachment on the APP treated surfaces.