Anal Chim Acta. 2026 Nov 1;1421:346039. doi: 10.1016/j.aca.2026.346039. Epub 2026 Jul 28.ABSTRACTIn light of the growing global burden of colorectal cancer (CRC), there is an urgent need for sensitive and non-invasive diagnostic tools. Here, we developed a novel whole-cell biosensor in Escherichia coli for the specific detection of fecal bile acid salts as biomarkers linked to CRC progression. Our platform integrated two modular sensing architectures: a synthetic hammerhead ribozyme switch tailored for primary bile acids (100-300 μM), and an engineered two-component system (VtrA/VtrC) from Vibrio parahaemolyticus that selectively responded to secondary bile acid salts such as deoxycholic acid (50-300 μM). To achieve clinically meaningful sensitivity, we employed two signal amplification strategies, combining a constitutively expressed LuxR/pLuxI module with a tandem multi-reporter gene array, resulting in a roughly 2.7-fold increase in fluorescence output; the tandem multi-reporter gene array alone contributed to a roughly 1.7-fold increase in fluorescence output. Through systematic optimization, a biosensing platform capable of translating complex fecal biomarker profiles into quantifiable signals was established. This work demonstrates a significant advance toward a non-invasive, user-friendly, microbe-based point-of-care diagnostic system for personalized CRC risk assessment.PMID:42702456 | DOI:10.1016/j.aca.2026.346039