Digital detection and quantification of SARS-CoV-2 in a droplet microfluidic all-fiber device

Silica fibers and capillaries offer opportunities for compact integration of optics with microfluidics while adding advantages such as;flexibility within a high aspect ratio format, uniaxial arrangements, and measurement-at-a-distance. Here, we describe droplet microfluidics-based nucleic acid detection of SARS-CoV-2 in a lab-in-a-fiber platform. The fiber component integrates three modules with key functions: droplet generation, incubation, and fluorescence detection. Within the scope of this work, we developed the component specifically to target the quantification of SARS-CoV-2 viral RNA through reverse-transcription loop-mediated isothermal amplification (RT-LAMP). The all-fiber component could successfully generate uniform droplets and differentiate pre-amplified positive LAMP reaction from negative sample. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.

Viral detection and quantification in a digital droplet microfluidic lab-in-a-fiber device

In this work, we present the design and fabrication of a fiber device that performs digital droplet microfluidics for molecular diagnostics. A variety of fibers and capillaries were used to build three connected modules dedicated to droplet generation, incubation, and fluorescence detection which enables a uniaxial arrangement. This is in contrast to the traditional 2-dimensional lab-on-a-chip architecture. We characterize our fiber device using a fluorescein dilution series. Our observed detection limit is on the order of 10 nM fluorescein. We demonstrate our all-fiber device for the fluorescence readout after loop-mediated isothermal amplification (LAMP) of synthetic SARS-CoV-2. Our results suggest that this fiber device can successfully distinguish between positive and negative samples in molecular diagnostics. We propose that our fiber device offers benefits over microfluidic chip techniques such as easier optical integration, much simpler sample loading, and faster diagnosis with high specificity and sensitivity. Keywords: All-fiber device, microfluidics, optofluidics, loop-mediated isothermal amplification (LAMP), molecular diagnostics, SARS-CoV2. © 2021 SPIE.