Electrochemical Genosensing Based on Rigid Carbon Composites. A Review

Abstract

The development of novel and sensitive assays for DNA hybridization and detection has become an increasingly important research field. The design and fabrication of DNA‐modified surfaces and materials that are reproducible, stable, and selective to complementary DNA sequences are the main goal in the development of emerging analytical tools such as DNA chips or user‐friendly diagnostic devices for detecting a few DNA sequences such as electrochemical genosensors. Carbon‐based materials are widely used for this task due to their electrochemical, physical, and mechanical properties; their commercial availability; and their compatibility with modern microchip fabrication technology. Various approaches for electrochemical DNA determination are reviewed, in which the common element is the use of rigid carbon composite material as the electrochemical transducer. A stable DNA layer can be easily obtained by physical adsorption of DNA on graphite‐epoxy composite (GEC). Moreover, a universal affinity platform for electrochemical genosensing can be easily achieved by modifying the graphite‐epoxy composite with avidin to obtain an avidin biocomposite (Av‐GEB) whereon biotinylated DNA can be rapidly single‐point attached. Additionally, DNA‐modified magnetic beads are easily attached to magneto graphite‐epoxy composite (m‐GEC). The main strategies for electrochemical genosensing when using rigid carbon composites such as electrochemical transducer are discussed. Parameters such as ease of preparation, robustness, sensitivity, surface regeneration, costs, and transfer to mass production of these different DNA detection strategies are also considered.

Keywords:

• Graphite‐epoxy composite
• avidin biocomposite
• DNA
• hybridization genosensor
• enzyme‐label electrochemical genosensor
• label‐free electrochemical genosensor
• amperometric genosensors
• DNA biosensor
• magnetic beads

Acknowledgments

Financial support from Ministery of Education and Science (MEC), Madrid (Project BIO2004‐02776), is acknowledged. M. I. P. acknowledges the financial support from the Juan de la Cierva Program from MEC (Madrid) and the Universidad Nacional del Litoral (Argentina).