Researchers at Johns Hopkins University developed a COVID-19 testing technology that is based on surface enhanced Raman spectroscopy (SERS) coupled with machine learning. The technique does not require sample preparation or special training and can deliver results in as little as 25 minutes, with an accuracy that is comparable to that of PCR, the current gold standard. Interestingly, the sensor material can be deployed in a standard chip format for personalized testing, but it can also be applied to frequently touched surfaces, such as door handles, or even as a wearable, to monitor environmental and personal viral exposure.
As much as we might wish it otherwise, the COVID-19 pandemic continues, albeit with reduced levels of death and suffering. The virus shows no signs of disappearing, but our technological response has largely blunted its ability to cripple our societies, at least for now. As always, testing is crucial in monitoring and controlling the spread of the virus, and these researchers from John Hopkins have made a contribution towards faster, more accurate and convenient testing technologies.
Their device is based on surface-enhanced Raman spectroscopy, which involves using a laser to investigate molecular vibrations in a sample. In this instance, they used a flexible field enhancing metal insulator antenna (FEMIA) array to enhance the Raman signal of the viral particles in a sample, allowing them to detect very low levels of the virus. A machine learning algorithm assists with signal analysis. The technology is easy to use, and provides an accurate result relatively rapidly, with the researchers reporting 92% accuracy and a wait time of about 25 minutes.
“The technique is as simple as putting a drop of saliva on our device and getting a negative or a positive result,” said Ishan Barman, one of the developers of the new sensor. “The key novelty is that this is a label-free technique, which means no additional chemical modifications like molecular labeling or antibody functionalization are required. This means the sensor could eventually be used in wearable devices.”
Interestingly, the new technology could serve a role as an environmental monitoring device, with the FEMIA arrays being applied to frequently touched surfaces and later analyzed to gauge levels of virus in the community. Another application is as a personal wearable, perhaps for healthcare staff who are at high risk of viral exposure, with later analysis providing an estimation of personal exposure.
“Using state of the art nanoimprint fabrication and transfer printing we have realized highly precise, tunable, and scalable nanomanufacturing of both rigid and flexible COVID sensor substrates, which is important for future implementation not just on chip-based biosensors but also wearables,” said David Gracias, another researcher involved in the study.
Study in Nano Letters: Label-Free Spectroscopic SARS-CoV-2 Detection on Versatile Nanoimprinted Substrates