Sensitivity enhancement for diagnostic assays


The COVID-19 pandemic has ushered in a new era of diagnostic testing. Patients now demand rapid results, and they want testing to happen in a safe and convenient setting. Regulatory agencies and the biotech industry are working together to meet this need. Fierce competition is emerging among the hundreds of tests that have now received Emergency Use Authorization during the COVID-19 pandemic. The biggest differentiating factor among tests is the limit of detection (LoD), which for SARS-CoV2 means the lowest amount of viral material that can be detected in a given sample. Limit of detection is a critical feature because each ten-fold increase in LoD is expected to increase the false-negative rate by 13%.1 In other words, lowering the limit of detection means fewer COVID-19 positive patients returning to their communities and unknowingly spreading the virus.


Researchers in the Cockrell School of Engineering at The University of Texas at Austin have developed a method to concentrate biomolecules in a fluid suspension to a specific location where they can be captured for detection. The technology works by passing a fluid sample through a chamber where bubbles are generated by laser-surface interactions. The bubbles accumulate biomolecules, like viral particles and their nucleic acids, to the bubble generating surface. That surface can contain probes that are able to capture the viral particles and transport them downstream for detection by immunoassay or PCR. The researchers reported in Nano Letters an order-of-magnitude enhancement of biomolecule detection and significantly faster assay times.2

This technique requires minimal sample processing and does not degrade the biomolecules. All diagnostics rely on physical interactions between the biomolecule and detection probe. This technology improves the limit of detection by increasing the frequency of biomolecule-probe interactions. Implementing this solution can speed up assays and make them more sensitive, effectively offering patients faster and more accurate results.


1 Arnaout, R., 2020. Version 1. bioRxiv. Preprint. Doi 10.1101/2020.06.02.131144

2 Kim Y., Nano Lett. 2020, 20, 10, 7020-7027. Doi 10.1021/acs.nanolett.0c01969