Radio-frequency gas discharge (RFGD) fluorination of polymers: Protein and cell interactions at RFGD-fluorinated interfaces

Abstract

Proteins naturally adsorb at foreign surfaces. Adsorbed proteins on biomaterial surfaces are important to the biocompatibility of medical implants and devices, as well as to uses in biosensors, diagnostics, separations and industrial bioprocesses. There is ample evidence that the composition, organization, and conformations of the proteins adsorbed at a foreign interface are sensitive to the composition, topography, and molecular mobility of the substrate surface. The protein layer can also change in all the above aspects with time. Thus, it is a dynamic, “living” coating whose character is a direct reflection of the character of the substrate surface. Therefore, it is not surprising that many researchers have modified biomaterial surface compositions in order to influence protein absorption and subsequent conformational changes. The gas discharge process is one of the more useful methods for modification of biomaterial surfaces. Surfaces may be ablated (or etched) in a process which removes material and creates a cleaner, but chemically-modified surface. Gas discharge may also be used to deposit a polymer-like coating of a new composition on the surface, such as silicone and fluorocarbon coatings on hydrocarbon polymer surfaces. Certain of these fluorocarbon discharge-deposited polymers have been shown to enhance retention of adsorbed proteins, presumably by increased hydrophobic interactions with the modified substrate. Furthermore, platelet adhesion on such surfaces may be increasingly reduced as the adsorbed protein is increasingly bound to the fluorinated surface. These unusual results and their biologic implications are discussed in this paper.