A lab-in-a-fiber component was fabricated using an optical fiber and a fiber capillary. It was used in a test suspension of fluorescently labeled and unlabeled cells and enabled detection of the labeled cells. Subsequently the labeled cells were selectively collected via suction into the capillary. A novel sampling technique reduced photobleaching of the labeled cells, extending the measurement time. The collected cells remained viable for downstream analysis. This platform’s low fabrication cost, simplicity, compatibility with standard laboratory equipment, and capacity for fully automated cell capture highlights its potential for future applications in minimally invasive sample collection and point-of-care diagnostics. We demonstrate this LiF device to showcase the capability of optical fiber technology in creating low-cost, low-complexity cancer diagnostic devices. Furthermore, the LiF device holds promise for in vivo diagnostics, facilitating cell isolation and analysis.

We present an optical fiber-based selective cell picking module capable of picking up and transferring single cells or clusters. Our Lab-in-a-fiber (LIF) module detects labelled cancer cells (MCF-7) and picks them up for further analysis.

We present an optical fiber-based selective cell picking module capable of picking up and transferring single cells or clusters. Our Lab-in-a-fiber (LIF) module detects labelled cancer cells (MCF-7) and picks them up for further analysis.

We present an optical fiber-based selective cell picking module capable of picking up and transferring single cells or clusters. Our Lab-in-a-fiber (LIF) module detects labelled cancer cells (MCF-7) and picks them up for further analysis.

We have developed an optical fiber-based module that can select, retrieve, and transfer single cells, and cell clusters. Cell picking and isolation has several applications such as separating circulating tumor cells, isolating single fetal cells for prenatal testing, and others. Our Lab-in-a-Fiber (LiF) module can detect fluorescent cancer cells (MCF-7) from a mixture of labeled and unlabeled cells and pick them up for further analysis. The cells picked up by the fiber show a 90% survival rate on viability tests, making this cell-picking technique an attractive alternative to existing methods.

An all-fiber integrated device capable of separating and counting particles is presented. A sequence of silica fiber capillaries with various diameters and longitudinal cavities are used to fabricate the component for size-based elasto-inertial passive separation of particles followed by detection in an uninterrupted continuous flow. Experimentally, fluorescent particles of 1 μm and 10 μm sizes are mixed in a visco-elastic fluid and fed into the all-fiber separation component. The particles are sheathed by an elasticity enhancer (PEO - polyethylene oxide) to the side walls. Larger 10 μm particles migrate to the center of the silica capillary due to the combined inertial lift force and elastic force, while the smaller 1 μm particles are unaffected, and exit from a side capillary. A separation efficiency of 100% for the 10 μm and 97% for the 1 μm particles is achieved at a total flow rate of 50 μL min−1. To the best of our knowledge, this is the first time effective inertial-based separation has been demonstrated in circular cross-section microchannels. In the following step, the separated 10 μm particles are routed through another all-fiber component for counting and a counting throughput of ∼1400 particles per min is demonstrated. We anticipate the ability to combine high throughput separation and precise 3D control of particle position for ease of counting will aid in the development of advanced microflow cytometers capable of particle separation and quantification for various biomedical applications.

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 similar to 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.

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.