Biological Applications of Atmospheric Pressure Plasma Liquid Deposition

Surface modification is a common methodology employed to make biomaterials more compatible with the biologic environment in which they will be used or to achieve some desired biologic effect. Many methods exist for modifying materials, each with their own set of advantages and disadvantages. Plasma technology is one way researchers choose to modify materials as it typically forms coatings that are uniform and exhibit good surface adhesion. Nonthermal plasma is most frequently used in the modification of biomaterials because it operates at ambient temperature, but it also operates at vacuum pressures. Dow Corning Plasma Solutions has developed a new technology termed atmospheric pressure plasma liquid deposition (APPLD) that generates a stable glow discharge plasma at ambient temperature and pressure. To this point, the applications of this new technology have been limited to the field of chemistry. The objective of this study was to explore biological applications of the APPLD technology as it pertains to the modification of biomaterials. The aims of this study primarily focused on the deposition of monomers and polymers to make cell releasing surfaces and biocidal surfaces. In general, it was found that the APPLD technology could be used more successfully for the deposition of polymers than monomers. This is most notably demonstrated by the extensive studies of N-isopropylacrylamide (NIPAAm) deposition. Contrary to what was expected, the polymerization of the NIPAAm monomer was very limited in the APPLD system. When the focus of the experiments shifted to deposition of poly(N-isopropylacrylamide) pNIPAAm, covalent modification of a high molecular polymer was observed. Only after this was cellular release, the desired biologic effect, observed. Similar observations were made for the deposition of biocidal monomers and polymers as the APPLD system again proved to be more effective when biocidal polymers were used as the liquid precursors. These findings have demonstrated that there is utility of APPLD for biological applications and has provided a base for future experimentation