Development and Characterization of a Plastic Microfluidic Spinning Disc for Protein Biomarker Assay in Space
Astronauts live and work in an environment with altered gravity, radiation exposure, isolation, and confinement, and they also have to deal with a high-stress job on a daily basis without access to medical care for months at a time. Because of this, monitoring their health is crucial to the success of the mission. In an attempt to enable a self-operated monitoring device for the detection of certain biomarkers in a liquid biopsy sample, a microfluidic disc device was designed, fabricated, and tested for the detection of human interleukin 6 (IL-6) and C-reactive protein (CRP) from a plasma sample with an ELISA protein array assay. The device uses centrifugal forces and surface tension to pump the fluids through the different chambers of the disc, and theoretical simulations and calculations were done to determine the spin speeds necessary to accomplish the microfluidic valving. Analytical testing confirmed the theoretical valves, and the fluids flowed reliably throughout the disc, even after many different cycles with different liquids. The on-disc direct and indirect sandwich ELISAA assays were demonstrated for Biotin-BSA, IL-6, and CRP. An initial on-disc dose-response curve was generated for Biotin-BSA and CRP, with detection sensitivities of 0.1µg/mL and 0.005µg/mL, respectively. This spinning disc device has a unique architecture, the ability to perform multiplexed assays, offers a low-cost and simple operation with the potential for integration with other bioassays, and provides a holistic overview of the health of astronauts.