Photoelectrochemical genosensors for the determination of nucleic acid cancer biomarkers

Liquid biopsy consists of a test or a series of tests carried out on a sample of blood to monitor circulating biomarkers, including nucleic acids. In cancer, a liquid biopsy approach can be useful not only for a rapid diagnosis, but also for therapy selection and cancer patient monitoring during treatment. However, the analytical assays need to be very sensitive (capable of detecting very small amounts of circulating analytes) as well as selective. Photoelectrochemistry is a powerful technique of developing an analytical biosensing assay, since it possesses advantages of both optical and electrochemical methods by coupling light excitation and electrochemical detection, and thus resulting in potentially very sensitive measurements due to the low background current. The aim of this review is to describe photoelectrochemical genosensors and to point out the potential of this class of genosensors in determining circulating nucleic acids as well as the challenges in the frame of a liquid biopsy approach.