ht-OMB.jpg Rapid, highly sensitive, and high-throughput detection of biomarkers at low concentrations is invaluable for early diagnosis of various diseases. In many highly sensitive immunoassays, magnetic beads are used to capture fluorescently labeled target molecules. Unfortunately, these assays usually do not provide the optimal combination of sensitivity, speed, throughput, and ease of use. There is always a trade-off between these essential qualities. For example, current diagnosis of the acute phase of the coronavirus disease 2019 (COVID-19) is based on direct detection of either viral antigens or viral ribonucleic acids (RNA) in swab samples. Antigenemia assays are simple to use, have fast turnaround times, and allow rapid testing for point-of-care applications. However, compared with viral RNA-targeting tests, their sensitivity is low, and they cannot screen multiple patients in a short period of time. Molecular assays to detect the viral RNA are highly sensitive, but usually time-consuming and laborious.

We have built, in our lab, a high-throughput optical modulation biosensing (ht-OMB) system, which uses a small permanent magnet to aggregate magnetic beads into a small detection volume and eliminates background noise by steering a laser beam in and out of the cluster of beads. Shortening the aggregation, acquisition, and well-to-well scanning transition times enables reading a 96-well plate within 10 minutes. Using the system to detect human Interleukin-8, we demonstrated a limit of detection of 0.14 ng/L and a 4-log dynamic range. Testing 94 RNA extracts from 36 confirmed RT-qPCR SARS-CoV-2-positive patients (C_t≤40) and 58 confirmed RT-qPCR SARS-CoV-2-negative individuals resulted in 100% sensitivity and 100% specificity.

In June 3rd, 2022, our paper on detection of low concentrations of biomarkers using high-throughput optical modulation biosensing (ht-OMB) system was published at "Talanta".

The paper, entitled 'High throughput optical modulation biosensing for highly sensitive and rapid detection of biomarkers', can be found in the Publications section, and at DOI: 10.1016/j.talanta.2022.123624

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