Capillary-driven flow microfluidics devices for point-of-care diagnostics

Abstract

Capillary-driven flow microfluidics offers the ability of loading samples into microchannels without the requirement for external pumping mechanisms. Microfluidics devices can be coated with specific reagents and a simple dipping into a fluid sample could trigger a reaction in between reagents and analytes of interest. There is a great potential to explore capillary-driven flow microfluidics and utilize it for point-of-care (POC) diagnostics e.g. for the prevention of antimicrobial resistance (AMR) in healthcare by loading bacterial/pathogenic samples into microchannels, incubating and reading the results near the patient’s bedside [1]. Several such devices have been developed for detection of biomarkers and AMR testing [1-3] along with smartphone detections which offer an alternative approach for portable point-of-need imaging requirements [4]. However, bacterial sample loading into microchannels could be challenging because of the surface properties of the microchannels and clogging of samples at the inlets. Recently, highly branched poly(N-isopropyl acrylamide) incorporating Nile red has been shown to provide a fluorescence signal upon binding to bacteria [5]. This paper showcases a capillary-driven flow microfluidics device (Chip-and-Dip) for loading of bacterial/pathogenic samples into microchannels for antimicrobial testing. This device offers the capability of capturing cells into microchannels that can be further treated with reagents to generate a colorimetric/fluorescent signal. The Chip-and-Dip device, fabricated with inexpensive materials and coated with these reagents, works by simply dipping the reagents-coated microfluidics chip into a sample. Here, we show a successful coating of microchannels with fluorescently labelled polymer and loading of Enterococcus Faecalis spiked in milk samples.