Characterization of a lab-on-chip for dual analyte assay in space missions

This paper presents an in-depth analysis of APHRODITE, a collaborative project involving the School of Aerospace Engineering (SIA) at Sapienza University of Rome, the Department of Chemistry “Giacomo Ciamician” of the University of Bologna, and Kayser Italia. Funded by the Italian Space Agency (ASI), APHRODITE serves as a technological demonstrator for deployment on the International Space Station (ISS) in late 2025, focusing on the determination of astronauts’ salivary biomarkers through an innovative biosensor. The manuscript delves into the design, manufacturing, and testing of its microfluidic chip focusing on the detection subsystem and detailing its microfluidic simulations, magnet selection study, and critical role in the assay process. The microfluidic chip integrates thin-film sensors in hydrogenated amorphous silicon (a-Si:H) for dual-analyte competitive chemiluminescence (CL) immunoassays. In addition, the work outlines the assay protocol, emphasizing the use of functionalized magnetic microbeads (MBs) for chip reusability and assay versatility, enabling multiple successive assays, and consecutively analyzing different target analytes. The project outlined herein seeks to advance biosensing technologies for health monitoring in space, offering an in-depth description of the APHRODITE detection subsystem and its essential role in performing real-time analysis of salivary biomarkers throughout space missions.