(G-257) Affordable Point-of-Care (POC) Microfluidic for Rapid Detection of Carbapenem Resistant Enterobacteriaceae (CRE) Infections

Introduction:: 63.8% of individuals contracting a carbapenem-resistant Enterobacteriaceae (CRE) infection will die within 30 days (1). The decreased survival is in large part due to the multi-day long delay in identification of a CRE infection and lack of identification of specific mechanisms. Self-coalescing flow microfluidics have been demonstrated by previous research groups as an ideal tool for multiplexed tests using a single sample, however, rely on complex lithography manufacturing methods, and high-cost syringe pumps and plate readers to run and interpret assay results (2). To that end, we implemented a novel manufacturing method to innovate a low-cost, standalone self-coalescing POC device that produces a rapid visually detectable colorimetric signal upon detection of CRE.


Materials and Methods:: The traditional self-coalescing design was scaled up and laser cut onto 0.13mm silicone-adhesive roll-based tape. 7 different width designs for the capillary pinning line (CPL) feature ranging from 0.25 - 2 mm (increasing by 0.25mm) were made to test for best preservation of the self-coalescing property. For functional testing three 0.20 µL spots of dried amaranth at a concentration of 30 mg/mL were manually micropipetted onto the surface of the channel (Fig A). DI was used as a test sample and introduced to the channel through syringe pump (2 µL/min) and through micropipetting (180µL). For the assay, 1.0 µL of reagents were spotted on the channel via micropipette. A micropipette was used to input 180µL of bacterial sample for a pH-dependent carbapenemase detection assay that outputs control and test colorimetric signals. The resulting colorimetric signal for carbapenem hydrolysis was interpreted by visual inspection.


Results, Conclusions, and Discussions:: Our testing revealed that devices were more prone to failure when loading by hand, which could inadvertently induce mixing between spatially separated reagents. We were largely able to mitigate this by changing the width of our capillary pinning line. A high success rate was achieved with preserving the self-coalescing flow pattern on a larger scale using the laser cut device through micropipetting using the 1.5-2mm CPL design (Fig C-F). Upon testing with assay reagents, the 2mm design was chosen for optimal performance due to changes in fluid dynamics from water to assay reagents. The colorimetric test output a strong signal that was easily detectable by eye to indicate the presence of CRE (Fig B).



We pioneered a new highly accessible method for rapid detection of CRE infections. The scaled-up design combines low-cost manufacturing and reduces the need for costly equipment to run and analyze the assay. Further optimization of the design will be done to achieve a higher success rate. The innovative application of a microfluidic POC diagnostic revolutionizes testing for all patient populations.




Acknowledgements (Optional): :

References (Optional): : 1) S. Sabino, et al. mSphere, vol. 4, no. 2, 2019.
2) O. Gökçe, et al. Nature, vol. 574, no. 7777, pp. 228–232, 2019.