Electrochemical biosensors: rapid detection methods in wastewater-based epidemiology research

Urban sewage carries a lot of information about human activities and is one of the most important links between humans and the natural ecological environment. During the COVID-19 pandemic, the tracking and monitoring of novel coronavirus loading in sewage have provided key data for the dynamic regulation of epidemic prevention and control policies. Thus, much attention has been paid to wastewater-based epidemiology (WBE), an innovative approach to monitor public health and chemical consumption. Correspondingly, there are large demands for analytical methods with high sensitivity, high selectivity and instantaneous response for detecting target markers in sewage. Electrochemical biosensors present great prospects in WBE research because of their high sensitivity, strong specificity, good operability and requirement of a less sample amount. This review provides an overview of the sensing structure, signal amplification strategies and sensing modes of electrochemical biosensors. The recent progress in the application of the four common types of electrochemical biosensors, enzyme-based, antibody-based, aptamer and molecularly imprinted polymer sensors, is introduced, including the sensing mechanisms, immobilization of biorecognition elements and strategies for improving the performance. Finally, the challenges and perspectives for the future development of electrochemical biosensors for WBE research are presented. The fundamentals, sensing mechanisms, strategies for improving the performance and the representative discoveries of electrochemical biosensors for the monitoring of various targets are summarized.