Plasma-polymerized films for biosensors

A biosensor is a useful tool for chemical, biochemical, medical and environmental fields because of its compact size, real time analysis, nearly reagentless operation, simple pretreatment protocols and simplicity of use. The performance of the biosensor often depends on how well the biological components are combined to the transducers, which is also referred to as 'immobilization of biological components' or 'interfacial design'. A plasma-polymerized film, achieved in glow discharge or plasma in vapor phase, offers a new alternative for use in the interfacial design of the biosensors. The properties of the film are that they (i) are extremely thin (<1 mu m), (ii) provide good adhesion to the substrate, (iii) are pin-hole free and present a flat surface structure, (iv) are mechanically and chemically stable because of the highly branched and cross-linked structure in the polymer, and (v) allow for a large amount of biological components such as enzymes and antibodies to be loaded onto the surface of the film because of its biocompatible characteristics. The films have potential for use in the interfacial design for biosensors from both a fundamental and a practical aspect. In this article, we review the usefulness of plasma-polymerized films as interfaces in biosensing applications. (C) 1999 Elsevier Science B.V. All rights reserved.