Development of innovative and versatile polythiol probes for use on ELOSA or electrochemical biosensors: application in hepatitis C virus genotyping.

The aim of this study was to develop versatile diagnostic tools based on the use of innovative polythiolated probes for the detection of multiple viruses. This approach is compatible with optical enzyme-linked oligosorbent assay (ELOSA) or electrochemical (biosensors) detection methods. The application targeted here concerns the rapid genotyping of Hepatitis C virus (HCV). HCV genotyping is one of the predictive parameters currently used to define the antiviral treatment strategy and is based on the sequencing of the viral NS5b region. Generic and specific NS5b amplicons were produced by real-time polymease chain reaction (RT-PCR) on HCV(+) human plasma. Original NS5b probes were designed for genotypes 1a/1b, 2a/2b/2c, 3a, and 4a/4d. Robust polythiolated probes were anchored with good efficacy on maleimide-activated microplates (MAM) and gold electrodes. Their grafting on MAM greatly increased the sensitivity of the ELOSA test which was able to detect HCV amplicons with good sensitivity (10 nM) and specificity. Moreover, the direct and real-time electrochemical detection by differential pulse voltammetry enabled a detection limit of 10 fM to be reached with good reproducibility. These innovative polythiolated probes have allowed us to envisage developing flexible, highly sensitive, and easy-to-handle platforms dedicated to the rapid screening and genotyping of a wide range of viral agents.