Graphite-epoxy platforms for electrochemical genosensing

The development of new transducing materials for DNA analysis, whose preparation is simple and suitable for mass fabrication, with a higher sensitivity and lower detection limits is a key issue in the research of electrochemical genosensing. In this context, the rigid carbon-polymer platforms reported here can meet these demands. Various approaches for electrochemical DNA determination are presented, in which the common element is the use of graphite-epoxy composite (GEC) as transducer. The first approach relies on label-free electrochemical genosensing. In this case, an inosine-substituted probe is adsorbed onto GEC by simple wet-adsorption. The detection of target DNA is achieved using its intrinsic guanine oxidation peak by DPV (differential pulse voltammetry). Other approaches are based in labeling procedures that use enzyme conjugates as markers: (i) GEC electrodes with changeable Nylon membranes (Nylon/GEC transducer), modified with DNA immobilized by physical adsorption; (ii) DNA directly adsorbed onto GEC using dry-adsorption, and (iii) electrochemical platform based on streptavidin-graphite-epoxy bio-composite (GEB), whereon biotinylated capture probe is immobilized by means of streptavidin-biotin reaction. The main advantages and problems associated with these GEC platforms and the strategies for electrochemical genosensing are discussed. Parameters such as ease of preparation, robustness, sensitivity, surface regeneration, costs, and transfer to mass production of these different DNA detection methodologies are also considered.