Optofluidic fiber- based nanoparticle tracking analysis: tool to characterize diffusing nanoscale specimen such as SARS-CoV-2

Schmidt, Markus; Wieduwilt, Torsten; Plidschun, Malte; Nissen, Mona; Jiang, Shende; Förster, Ronny

doi:10.1117/12.2597806

Cited by 1 publication

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“…Most recently, we have demonstrated particle separation and counting in an uninterrupted flow through a fiber device 31 . Furthermore, structured hollow core fibers allow for the guiding of light directly in the fluid media, which has been used for Raman sensing 32 and for the tracking of diffusion of nanoscale objects 33 , 34 including virus particles 35 . Structured optical waveguides, such as light cages, have been developed for absorption spectroscopy with possible applications in bioanalytics 36 .…”

Section: Introductionmentioning

confidence: 99%

A Lab-in-a-Fiber optofluidic device using droplet microfluidics and laser-induced fluorescence for virus detection

Parker

Sengupta

Harish

et al. 2022

Sci Rep

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Microfluidics has emerged rapidly over the past 20 years and has been investigated for a variety of applications from life sciences to environmental monitoring. Although continuous-flow microfluidics is ubiquitous, segmented-flow or droplet microfluidics offers several attractive features. Droplets can be independently manipulated and analyzed with very high throughput. Typically, microfluidics is carried out within planar networks of microchannels, namely, microfluidic chips. We propose that fibers offer an interesting alternative format with key advantages for enhanced optical coupling. Herein, we demonstrate the generation of monodisperse droplets within a uniaxial optofluidic Lab-in-a-Fiber scheme. We combine droplet microfluidics with laser-induced fluorescence (LIF) detection achieved through the development of an optical side-coupling fiber, which we term a periscope fiber. This arrangement provides stable and compact alignment. Laser-induced fluorescence offers high sensitivity and low detection limits with a rapid response time making it an attractive detection method for in situ real-time measurements. We use the well-established fluorophore, fluorescein, to characterize the Lab-in-a-Fiber device and determine the generation of $$\sim$$ ∼ 0.9 nL droplets. We present characterization data of a range of fluorescein concentrations, establishing a limit of detection (LOD) of 10 nM fluorescein. Finally, we show that the device operates within a realistic and relevant fluorescence regime by detecting reverse-transcription loop-mediated isothermal amplification (RT-LAMP) products in the context of COVID-19 diagnostics. The device represents a step towards the development of a point-of-care droplet digital RT-LAMP platform.

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