Biosensors in environmental monitoring: Adaptation of electrochemical detection of DNA using ferrocene containing cationic polythiophene to carbon fiber DNA working electrodes

Abstract

The detection of specific DNA sequences is of significance in many areas including clinical, food, biological warfare agent and environmental analysis. The increasing number of potentially harmful pollutants in the environment calls for fast and cost-effective analytical techniques to be used in extensive monitoring programs. Biosensors can be used as environmental quality monitoring tools. For environmental applications, the main advantages offered by biosensors over conventional analytical techniques are the possibility of portability, miniaturization, work on-site, and the ability to measure pollutants in complex matrices with minimal sample preparation. Carbon fiber microelectrodes (CFMEs) have not been used in electrochemical DNA biosensor for environmental monitoring. The ever increasing sensitivity and selectivity of CFMEs will facilitate detection of even lower concentration of analytes and the number of detectable and biologically important species will probably increase. In this study, immobilization and hybridization techniques for CFMEs were determined. In order to enhance the selectivity and sensitivity of the biosensor, ferrocene-containing cationic polythiophene [1,2] and derivatives were synthesized (Figure 1) and used with nucleic acids as capture probes on the CFMEs. The interactions between ferrocene-containing cationic polythiophene and nucleic acids immobilized on CFMEs are followed as electrochemically.