Parameter optimization of O2/He atmospheric pressure plasma for surface modification of poly (L-lactic) acid oriented fiber membranes: Improving cell adhesion and proliferation

Abstract

Non-thermal atmospheric pressure plasma jet (APPJ) is an effective tool for modifying surface properties and improving the biocompatibility of polymers owing to its advantages of simple structure, low cost, and flexible capacity. Effects of APPJ treatment on surface properties are influenced by operating parameters such as applied voltage, gas ratio, and treatment time. In this study, we investigated how these parameters affect surface properties of poly (l-lactic acid) (PLLA) fiber membranes when the O2/He APPJ treatment was employed, and optimized parameters for improving cell adhesion and proliferation. Specifically, highly oriented PLLA fiber membranes were fabricated via electrospinning and then treated using the O2/He APPJ with different processing parameters. Gelatin grafting was also performed on a sub-set of APPJ-treated PLLA membranes. We investigated electrical properties and optical emission spectra (OES) of APPJ, and employed water contact angles (WCA), X-ray photoelectron spectroscopy (XPS) analysis to examine changes of surface properties. Processing parameters were optimized based on experimental results. Cell culture studies showed that attachment and spreading of cells on the APPJ-treated membranes were much better than on untreated samples, and a significant increase of cell proliferation rate was observed for the APPJ-treated membranes under the optimized processing parameters. The optimization method presented has potential to be applied in similar APPJ-based surface treatment, which in turn broaden applications of APPJ in modifying surface properties of biopolymers.