Plasma treatment of biomedical materials

Abstract

Surface plasma treatment techniques for modification of biomedical polymeric materials are presented. The emphasis is on the use of non-equilibrium radiofrequency (RF) oxygen and nitrogen plasma. By variation of discharge parameters (power, discharge frequency, type of gas) and plasma parameters (density of neutrals and ions, kinetic energy of electrons, gas temperature) it is possible to produce polymer surfaces with different surface properties. Already after short plasma treatment time the surface of polymeric material becomes hydrophilic. Formation of nitrogen and oxygen functional groups is observed immediately after plasma treatment. By optimisation of plasma treatment time the number of newly formed functional groups can be increased. Plasma treatment also produces morphological changes of the surface; nanohills of different shapes and height can be formed on PET surface depending on the treatment time and type of gas. Evidently the change in surface morphology affects the change in surface roughness, which increases with longer plasma treatment time. Plasma treatment influences also on the biological response, as all plasma treated surfaces exhibit improved proliferation of fibroblast and endothelia cells. The number of adherent platelets practically does not change after nitrogen plasma treatment, however much lower number of adherent platelets is observed on oxygen plasma treated surfaces.