Development of an Automated Diagnostic Platform for SARS-CoV-2 Monitoring in Vulnerable Areas

Background: The devastation caused by emerging pathogens with fast transmission capacity, such as SARS-CoV-2, has demonstrated the importance of preparedness for future viral outbreaks. Preparedness requires tools for rapid in-situ testing and epidemiological surveillance with high temporal and spatial resolution, particularly in places vulnerable to becoming reservoirs of infectious agents.

Materials/Methods: This study developed a versatile multiplexing detection platform for SARS-CoV-2 in saliva. The system integrated signals from different biorecognition elements by immobilizing aptamer, antibody, and ACE2 onto laser-inscribed graphene electrodes. Detection mechanisms targeting the SARS-CoV-2 spike protein were studied under varying testing conditions, including pH, temperature, and ionic strength. After determining optimal operating conditions for each biosensor, a self-referencing approach was employed between complementary recognition elements (aptamers, antibodies, and ACE2 enzyme biosensors) to evaluate effects on test accuracy, including risks of false-positive and false-negative results. A saliva pre-treatment protocol was also developed to support SARS-CoV-2 detection in human saliva with the multiplex biosensor platform. In addition, an open-channel microfluidics system was designed to automatically split and channel a single saliva sample into multiple biosensor streams without saturation, biofouling, or the need for a pump.

Outcome/Impact: The outcome of this work was the development of a functional and reliable multiplex biosensor system for SARS-CoV-2 detection in saliva. The platform addressed longstanding public health needs and provided a foundation for rapid testing technologies to manage the continuing seasonal presence of coronaviruses, much like influenza, which may recur for decades with varying degrees of virulence.