Multimodal microfluidic sensor for harmful bacteria detection: Integrating nanozyme catalysis, SERS, and photothermal sterilization

This study presents the development of a multifunctional microfluidic chip designed for the rapid detection and inactivation of hazardous bacterial contaminants in complex environmental and industrial settings. The chip integrates nanozyme cascade colorimetric reactions, surface-enhanced Raman spectroscopy (SERS), and photothermal sterilization, enabling multimodal bacterial detection and decontamination. Constructed using Au@Fe/ZIF nanomaterials, the platform exhibits robust glucose oxidase (GOx)-like and peroxidase (HRP)-like activities, facilitating quantitative bacterial analysis through enzyme cascade reactions and highly sensitive species identification via SERS. For both Brucella melitensis and Bacillus cereus , the system achieves a detection limit as low as 10 CFU/mL both by SERS detection and enzyme cascade colorimetric analysis, with strong correlation (R 2  = 0.988) to standard plate counting. Additionally, Au@Fe/ZIF demonstrates high photothermal conversion efficiency (45.2 %), resulting in an inactivation rate exceeding 98 % under near-infrared irradiation. The platform's reusability and high detection accuracy make it a promising tool for monitoring bacterial hazards in contaminated water, industrial waste, and biothreat scenarios, offering a novel approach to biosafety and hazardous material management.