Fluorogenic squaraine dimers for the flow cytometry detection of bacterial urinary tract infections

Abstract

Rapid diagnosis of bacterial infections is essential for guiding antibiotic treatment and mitigating the global spread of antibiotic resistance. Here, we report the development of fluorogenic bacteria-specific probes for rapid flow cytometry detection of urinary tract infections. These probes, composed of a covalently linked pair of squaraine dyes conjugated to a bacteria-specific peptidic vector, exploit the phenomenon known as aggregation-caused quenching. The chemical structure of the squaraine dyes was finely tuned to ensure selectivity for bacteria over eukaryotic cells and human serum albumin. The most effective probe enabled semi-quantitative detection of bacteria in patient urine samples, with a total time-to-result of less than one hour.