On the Application of Gas Discharge Plasmas for the Immobilization of Bioactive Molecules for Biomedical and Bioengineering Applications

Abstract

Biomedical and biotechnological applications of polymeric materials often require specific interactions of the substrate surface with the biochemical or biological milieu. However, the standard surface properties of polymers like polystyrene (PS), polycarbonate (PC), polypropylene (PP), fluorinated ethylene polypropylene (FEP) or cyclic olefin copolymers (COC) do not meet these requirements. Therefore, the creation of functional surfaces is a very important topic to meet the requirements of advanced applications in bioengineering. For this purpose, gas-discharge plasmas offer some unique possibilities (Ohl & Schroder. 2008; Schroder et al., 2010a). They can lead to surface activation and functionalization, often not obtainable with conventional, solvent-based chemical methods. In addition, the superior chemical reactivity of plasmas allows surface activation of inert materials down to the nanoscale range including the creation of covalently bound functional groups in such small structures (Meyer-Plath et al., 2003). While it is possible to implant substances into the substrate and to etch surface structures by gas discharges, properly operated plasma processes might as well neither affect bulk materials characteristics nor produce undesirable substances and cause only minor thermal load to substrates (Schroder et al., 2011). Plasma processes are especially suitable for the equipment of polymer surfaces with chemical functional groups. Plasma functionalizations as well as depositions of nanometer-thick coatings with chemical groups can be used to receive the required biological response, for instance to control the cell density, distribution, adhesion and differentiation (Wende et al., 2006). Furthermore, plasma based processes can be combined with lateral pattern generation. Common mask techniques are suitable to create