DisCoVer: Aptamer biosensors for the detection of SARS-CoV-2 on surfaces

The high survivability of SARS-CoV-2 on surfaces, such as metal, plastic, glass and some fabrics, means that fomite transmission is likely to play a key role in the spread of nosocomial COVID-19 infections. With effective vaccines or counteractive drugs against the virus yet to be fully realised, effective monitoring of surfaces potentially contaminated with SARS-CoV-2 is vital to managing infection rates and protecting healthcare workers.

However, such environmental monitoring efforts are limited by the length of current viral testing processes (i.e. through swabbing, genomic extraction and RT-PCR), which prevents the identification of viral contamination in real-time. Biosensors, a group of molecules able to produce measurable signals in response to biological interactions, may overcome these challenges by allowing the rapid, specific and sensitive detection of SARS-CoV-2 in situ, without the need for extensive processing or specialised equipment.

This work will therefore involve the development of an optical biosensor towards SARS-CoV-2 based on aptamer recognition. Through delivery to surfaces as part of an aerosolised spray reagent, this sensor will allow the 'stand-off' visualisation of viral deposits through the production of discrete areas of fluorescence thereby allowing healthcare workers to quickly triage objects in need of decontamination.

Biosensor construction will be based on a 'molecular beacon' design, in which an initially quenched dual-labelled probe is restored to a fluorescent state upon SARS-CoV-2 binding. Fluorescence emission signals will be provided by bright and highly stable conjugated polymer nanoparticles, whilst molecular dynamics simulation and modelling studies will be

used to ensure high biosensor specificity/sensitivity.