European scientists are developing a laser sensor that detects coronavirus at the earliest point of infection from a saliva or nasal swab within minutes.
Responding to the European Commission’s Express Calls to tackle the coronavirus pandemic, scientists are developing a new rapid, non-invasive optical biosensor demonstrator that will detect Covid-19 in humans as soon as it is present in the body.
Originally developed to look for bacterial infections or cancer biomarkers, the new detector uses photonics to detect infections in patients with a small amount of the virus.
Having already created six working laboratory demonstrators for other applications, the research team says the technology still needs further adaptation and testing but could be available in a year at the latest.
With the ability to diagnose in real time with high specificity from a low concentration sample, the sensor is much more reliable than the coronavirus rapid-test, ‘finger-prick’ kit which detects if a person has had the coronavirus before and has since recovered.
The new point-of-care detector examines virus antigens using nanophotonic biosensors capable of detecting RNA strands.
Once a sample is prepared and is in place, the device confirms a positive or negative for coronavirus instantaneously. However, allowing for preparation time and analysis, a result - from sample to diagnosis - may take up to 30 minutes.
Named 'CONVAT' and coordinated at ‘ICN2’ (the Catalan Institute of Nanoscience and Nanotechnology, Spain) the researchers have tested the demonstrators on patients’ samples provided by Vall D´Hebrón Hospital in Barcelona and several other hospitals in Spain for other pathologies.
Project coordinator, Professor Laura Lechuga said: 'With thousands of deaths worldwide, we are in urgent need of a rapid new testing kit that is accurate, highly sensitive, non-invasive and cheap to produce.
'We are currently integrating all the instrumentation in a portable 25 x 15 x 25cm box with a tablet control. At present, our detector is user-friendly, with the preparation being only technical expertise required, and could be widely deployed for GPs or nurses to test patients.'
The detector works by looking at the ‘binding’ of the coronavirus molecules to the sensor surface - producing a new signal when the virus is present.
The CONVAT team use a nano-interferometric biosensor, a sensitive, label-free detection technology, to identify at the molecular level.
Since the bioreceptors on the sensor surface are specifically ‘tuned’ to a particular antigen of the virus, only the coronavirus molecules are captured along the sensor.
Light travelling in the sensor generates an evanescent field of few nanometres over the sensor surface. Here, receptors (like antibodies or DNA strands) can recognise the antigens of the virus capsid, when a respiratory fluid sample passes through.
This recognition event produces a change in the refractive index, causing the light to slightly change its direction of travel.