neoLAMP for simple and rapid detection of SARS-CoV-2

The Corona pandemic leads to noticeable disruptions in professional and personal lives, with drastic consequences for the global economy. To address the medical crisis, breaking chains of infection is crucial. The basis for this is reliable testing methods that enable infections to be detected quickly and effectively. Fraunhofer IME researchers have developed a new SARS-CoV-2 test method. This reduces the previous detection time of about four hours to less than one hour - and by eliminating complex, costly analytical equipment, on-site testing is possible.

© iStock | Naeblys
© Fraunhofer | Crispin-Iven Mokry
© Fraunhofer IME | Lena J. Freund

Test result in less than one hour

Researchers of the department “Functional and Applied Genomics” developed a simple, robust and rapid test for plant virus. Due to the special pandemic situation, they further adapted it for the detection of SARS-CoV-2. The new test method shortens the previous detection time of about four hours to less than one hour - and by eliminating complex, costly analytical equipment, on-site testing is possible. In contrast to other rapid detection methods, such as antigen test, this is achieved with the so-called loop-mediated isothermal amplification method (LAMP). The underlying principle of this method is based on the detection of parts of the viral genetic information. In contrast to the current standard test, the detection reaction is not relying on a polymerase chain reaction (PCR), but on the isothermal amplification of the desired target sequences of the virus.

Easy handling

Instead of a deep throat or nose swab, which many find unpleasant, the new test (neoLAMP) can also be performed via a mouth rinse or anterior nasal swab. This is possible without any further time-consuming purification of the samples. Our neoLAMP is more sensitive and reliable than the antigen rapid test, as known from testing centers, but easier and faster than the gold standard PCR. For a reliable result two independent regions of the viral genome are amplified. This ensures that even if different viral variants occur, the probability of a correct test result is not diminished. The simple detection of the result is similar to the antigen rapid test by means of a test strip (lateral flow dipstick). If the test is positive, a clear red line appears. In addition to the internal control line on the test strip, an extra line indicates the presence of the human actin gene from mucosal cells in the swab. This serves as proof of correct sample collection and test functionality.

Reliable results

In numerous laboratory tests, even samples with very low viral loads could be reliably detected with our neoLAMP. The detection limit is about 104 viral copies per milliliter sample - this is about a factor of one hundred to one thousand below the threshold value described by the RKI as just infectious. Clinical patient samples were also examined - the test proved to be sensitive and specific and thus showed very good agreement with reference PCR results. Different virus variants were very well detectable. In addition, initial laboratory results show that by adapting the test, it is also possible to specifically distinguish between variants. The development of the SARS-CoV-2 neoLAMP was funded by the Fraunhofer-Gesellschaft from the program "Fraunhofer vs. Corona.

Plant pathogens

 

The LAMP test for the detection of plant viruses.