A versatile colorimetric array sensor based on FeCu-based prussian blue analogue heterostructures for efficient discrimination of tetracycline antibiotics and rapid identification of urinary tract infection pathogens.

Precise discrimination of tetracyclines (TCs) with highly similar chemical structures remains challenging for nanozyme-based sensing platforms. At the same time, rapid and reliable identification of pathogenic bacteria, including urinary tract infection (UTI) pathogens, remains limited, hindering targeted antibiotic use and contributing to antibiotic abuse. In this study, three FeCu-based Prussian blue analogues (PBAs) with adjustable laccase (LAC)-like activity and diverse recognition sites were synthesized and assembled into a three-channel, dual-application colorimetric sensor array for sensitive discrimination of multiple TCs and UTI bacteria. Upon exposure to different TCs or bacterial species, distinct response patterns were observed and analyzed using principal component analysis and hierarchical clustering analysis. As a result, four TCs were selectively identified in river water, honey, chicken, and human urine samples using smartphone-assisted hydrogel- and paper chip-based colorimetric sensors, achieving a minimum detection limit of 1.41 nM. More importantly, the sensor array enabled rapid and specific discrimination of four common UTI pathogens in human urine within 10 min and further achieved in situ bacterial inactivation within 2 h. This versatile colorimetric sensor array shows strong potential for the authentication of TC and UTI pathogens in environmental, food, and clinical samples. This study presents a highly sensitive dual-application sensing strategy for rapid TC detection and UTI pathogen identification, offering a practical approach to pathogen differentiation and rational antibiotic use.