Reusable 3D-Printed microfluidic-on-Fabric with Modular Electrodes for Point-of-Care Na+ and K+ Detection in Various Biofluids

In this study, we present a new 3D-printed microfluidic-on-fabric sensor platform that allows for point-of-care (POC) detection in various biofluids. Using the low-cost FDM 3D-printing, we developed a method to form well-defined microfluidic features on fabric substrates (3D-printed microfluidic-on-fabric), which could modularly house an electrode pad with desired electrodes targeting different analytes. The 3D-printed microfluidic-on-fabric integrates the comfort, robustness, and reusability (after washing) of fabric substrates with the precision, modularity, and scalability offered by 3D-printed structures. We showcased the application of the sensor platform for Na+ and K+ detections with lab-made ion-selective electrode pads. The electrodes showed high reusability, in addition to the robust Nernst sensitivity, accuracy, selectivity, and reproducibility. The sensors platform was successfully implemented to detect Na? and K? in a range of biofluids, including urine, saliva, and sweat, with results validated by ion chromatographic methods. An Arduino board (~$20) was programmed to couple to the sensor for data collection, transducing, processing, and transferring to a computer. Overall, this is a new sensor platform that is low-cost, reusable, modular, and customizable, representing an advancement in POC sensor development.