ATMOSPHERIC PLASMA SURFACE MODIFICATION OF ELECTROSPUN POLY(L-LACTIC ACID): EFFECT ON MAT PROPERTIES AND CELL CULTURING

Material science applied to regenerative medicine and tissue engineering study the achievement of biocompatible artificial tissues to improve, self-repair or favour cellular therapies. Various studies prove plasma ability to modify polymeric scaffold surface, with an improvement of hydrophilicity and surface roughness demonstrated by a reduction of contact angle and by an increase of surface energy without altering bulk properties. Furthermore, it was demonstrated that cell cultures on plasma modified scaffolds display better proliferation and viability compared to pristine materials. In this work we focus on the use of atmospheric pressure non-thermal plasma for surface modification of electrospun poly(L-lactic acid) (PLLA) non-woven mats. The electrospinning technology allows to fabricate scaffolds of polymeric materials with highly porous structure, interconnected pores and large specific surface area, that mimic extracellular matrix (ECM). In this work results will be presented concerning the process of exposure of electrospun scaffolds to the plasma region generated by three different plasma sources operated at atmospheric pressure: a floating electrode dielectric barrier discharge (FE-DBD), a linear corona discharge and a DBD roller. A high voltage generator capable of producing pulses with a rise rate in the order of some kV/ns has been used. All the sources are easily scaled-up in the frame of a "large area treatment" approach. Plasma sources characterization has been carried out through a wide set of measurements, changing operating conditions, geometry and plasma gas composition, as the fundamental stage in a multi-step approach for process optimization. In this work, results on the effect of plasma treatment on morphology, thermo-mechanical and surface properties of PLLA electrospun nanofibrous mats will be presented. Results for the introduction of COOH functional group on PLLA electrospun scaffold and for the proliferation of rat embryonic stem cells (RESCs) grown on plasma treated and untreated PLLA electrospun scaffolds will be presented and discussed.