Bioaffinity platforms based on carbon-polymer biocomposites for electrochemical biosensing

Abstract

Rigid conducting biocomposites are interesting transducing materials for the construction of electrochemical immunosensors, genosensors and enzymosensors, particularly if the material is modified with universal affinity biomolecules. Examples of these ‘universal affinity biocomposites' for electrochemical biosensing are reviewed, in which the common base material is a graphite–epoxy composite. The first approach relies on strept(avidin)–graphite–epoxy biocomposite transducer, as a universal immobilization platform whereon biotinylated biomolecules, such as DNAs, enzymes or antibodies can be captured by means of strept(avidin)–biotin reaction. The second approach is based on Protein A–graphite–epoxy biocomposite. Protein A is able to bind the Fc region of antibodies serving as generic affinity matrix for immuno-immobilization on the transducer. Biocomposite electrodes offer many potential advantages compared to more traditional electrodes based on a surface-modified conducting phase. The capability of integrating various materials into a single one is their main advantage, besides the improved electrochemical properties. These materials can just be prepared through ‘dry chemistry’ using procedures that can be easily transferred to mass fabrication of thick film devices. The different properties of these materials are discussed. Analytical response as well as other parameters such as the easiness in preparation, robustness, sensitivity, surface regeneration, costs, and transfer to mass production of these different approaches is also considered.