RAPID: COVID: Optofluidic sensor array for rapid and sensitive detection of COVID-19 antibodies

Engineering - COVID-19 has caused tens of thousands of deaths and is becoming a severe threat to global health. One of the methods to detect COVID-19 infection, track the treatment effectiveness, and validate successful vaccination, is to measure the antibodies developed in human bodies. Unfortunately, current antibody detection relies on either complicated instruments in a centralized lab which is expensive and takes a long time to get the results, or a paper-based test strip, which, while quick (5-20 minutes), produces only Yes/No results, making this method very easy to generate false positives/negative and impossible to track the patients? response to infection, treatment, and vaccination. Therefore, a portable device that can rapidly, sensitively, and accurately measure multiple COVID-19 related antibodies is urgently needed to diagnose early infection and monitoring patients? response. The device in the project is based on a portable microfluidic system to rapidly, accurately, and sensitively measure the antibodies in blood at point-of-care, which allows for the detection of COVID-19 infection and tracking of antibody development in human bodies.

The objective of the project is to combine microfluidic laser technology and microfluidic ELISA (enzyme-linked immunosorbent assay) technology to develop rapid and highly sensitive sensor array for multiplexed detection of COVID-19 related IgG and IgM using fingertip blood. There are three tasks: (1) to develop a microfluidic chip to extract serum from whole blood; (2) to integrate the laser sensing technology with traditional fluorescence ELISA to sensitively detect antibodies (IgG and IgM) with a large dynamic range; (3) to test with artificially spiked samples. The device provides the following advantages. (1) Quick turn-around time. It is highly portable and can be used to rapidly screen patients on-site, rather than sending samples to centralized labs. (2) Highly quantitative. This is critical to significantly reducing the false positives/negatives and monitoring the patients? infection trajectories and response to treatment and vaccination. (3) Highly sensitive and large dynamic range. Combined with the lasing technology, we expect to improve the antibody detection limit 10X with 10X larger dynamic range. Higher sensitivity enables earlier diagnosis of infection, preventing wide disease spread from those asymptomatic patients. A large dynamic range enables to easily track patients? antibody evolution over time. (4) Highly versatile. The device can be adapted to rapidly detect cytokine release syndrome (CRS), which is one of the death causes in COVID-19 patients.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.