Rapid, Ultrasensitive Proximity Ligation Assay Potent SARS-CoV-2
Straightforward, specific, and ultrasensitive detection of SARS-CoV-2 for controlling and containing the coronavirus pandemic is currently a significant global challenge necessary for the prevention of the unwanted spread of the virus. Currently, there are two main types of detection tests: one is a serological immunoassay that detects antibodies post-exposure, and the other is an RT-PCR assay that confirms the presence of the virus in a sample of interest. Serological assays rely on the immune response of an individual and require drawing a blood sample. As such, this method is not suitable for testing surfaces and other non-human samples for the presence of the virus. Further, reverse-transcription PCR (RT-PCR) provides sensitive and specific information about whether COVID RNA is present in a sample. However, the presence of the viral RNA does not necessarily indicate that a sample of interest is infectious, and further requires RNA isolation using an additional chemical treatment. Therefore, the presence of the RNA in alcohol- or detergent-treated samples, for example, cannot confirm that the sample of interest is not infectious. Only a method that can confirm the presence of an intact SARS-CoV-2 particle can confirm that a sample has the potential to infect an individual.
Northeastern University researcher Dr. Meni Wanunu has designed a diagnostic method that can detect the presence of intact SARS-CoV-2 virus capsids, which is the best possible proxy for active, infectious virus. This methodology is ultra-sensitive (with potential to detect even one virus per sample), draws from standard molecular biology tools and reagents, and can detect viruses in vivo or on surfaces. The diagnostic method can be formulated into detection kits that support rapid high-throughput testing, or rapid self-administered tests.
- Test takes as long as a normal PCR test (~1 hour), and provides a clear-cut response for infectivity, and is compatible with pooled PCR testing by using unique-sequence design reporters
- Test results will support much better decision-making in terms of when to practice isolation and when to seek medical attention
- Simplicity of the basic testing approach allows it to be modified to a number of distinct, highly practical use cases
- This assay would result in a kit to detect as few as one SARS-CoV-2 particle in a sample
- For facilities equipped with PCR expertise (potentially an airport, for example) prospective passengers could be evaluated for active virus within about an hour. This technology could alternately be deployed on a population-scale, by collecting saliva samples across a community of potentially exposed individuals and sequenced, generating test results for millions of patients within about two days
- Workflow can be coupled with reverse transcription-polymerase chain reaction (RT-PCR) for more specific genotyping of the virus
- Meni Wanunu
- Proximity Ligation Assay for Detection of SARS-CoV-2 Novel Coronavirus Particles