The SARS-CoV-2 virus can be detected through two popular tests. First, a rapid test that detects specific viral proteins. The other one is PCR (polymerase chain reaction) tests. However, both assays are relatively time-consuming. Further, neither of the tests can precisely determine the virus's presence. Even the gold-standard PCR tests could have a false-negative rate of above 25%.
A novel method of detecting the virus that causes Covid-19 could lead to faster and less expensive tests. A team has unveiled an approach to develop tests less prone to false positives than current detection methods. Though the discovery based on quantum phenomena is still speculative, it could immensely benefit the COVID-19 Diagnostic Market as these tests would have less than a 1% chance of false negatives.
The researchers believe that if the detectors produced are appropriately advanced, they will detect almost any infection. Furthermore, the test may be sensitive enough to detect a few hundred strands of viral RNA in less than a second.
The novel method utilises nitrogen-vacancy (NV) centers, which are atomic-scale flaws in microscopic diamond pieces. As quantum processes occur in the diamond's crystal lattice, these microscopic flaws are extraordinarily sensitive to slight perturbations. Researchers decided to investigate these flaws for a range of sensing systems that require great sensitivity.
The new procedure entails covering the nanodiamonds with a magnetically linked substance. These nanodiamonds contain the NV center and have been modified to connect with the virus's unique RNA sequence. When the virus' RNA binds to this material, it destroys the magnetic link. Thus, producing changes in the fluorescence of the diamond, which may be easily detected with a laser-based optical sensor.
The team-added sensor is made of low-cost materials (the diamonds used are smaller than dust particles). The researchers claim that it may be scaled up to evaluate many samples at once. The RNA-tuned organic molecules in the gadolinium-based coating can be made with standard chemical methods and materials. Further, the lasers used to read the results are akin to cheap, widely available commercial green laser pointers.
The team stated that technology fundamentals could be modified to suit any virus. This can be achieved by changing the chemicals connected to the nanodiamond sensors to match the available material of the target virus. The statement includes any new ones that may emerge as well.
The proposed method appeals to people because of its generality and technological simplicity. Compared to existing approaches that use nitrogen-vacancy centers, the sensitive, all-optical detection methodology described here requires minimum instrumentation.