Electrochemical Detection of RNA

Over the past few decades, it was demonstrated that RNA plays a central role for a wide range of functions in living cells through control of the gene expression. This chapter focuses on different electrochemical detection approaches of RNA with applications in clinical diagnostics as well as in food and environmental analysis. Electrochemical biochips are an emerging tool for point-of-care diagnostic systems due to their inherent high sensitivity along with cost and time effectiveness. In this review, different strategies of electrochemical biosensors for direct RNA detection will be compared. Additionally, the implementation of nanotechnology as a powerful alternative to common detection approaches will be addressed. Specific detection of 16S ribosomal RNA allows species-specific identification of bacteria without a prior nucleic acid amplification step. Examples of 16S rRNA detection describe the analysis of pathogens in food samples, indicator bacterium Escherichia coli in water samples, or uropathogens in clinical samples. Additionally, messenger RNA-based bacteria detection was applied by several research groups for species-specific bacteria identification. Beside bacteria detection, direct detection of viruses that contain RNA as genetic material is feasible. Electrochemical messenger RNA detection enables the determination of mRNA levels in cells and, thus, the evaluation of different cell populations or cell status. The abnormal expression of microRNAs in malignant cells makes microRNAs promising biomarkers for cancer diagnostics. Therefore, different electrochemical biosensing strategies for direct microRNA profiling will be compared.