Engineered CeO2−x/Au Nanocomposite Enabled Colorimetric‐Terahertz Bimodal Sensing of Urinary Tract Infection Pathogens

Abstract

The integration of rapid on‐site screening with precise quantification is critically important for the diagnosis of urinary tract infections (UTIs). However, current detection methods often struggle to balance between screening efficiency and quantitative accuracy. Herein, we first report a colorimetric‐terahertz (THz) dual‐mode sensing platform powered by CeO2−x/Au nanospheres for pathogenic bacteria in UTIs. The engineered CeO2−x/Au nanospheres exhibit outstanding peroxidase‐like activity and dielectric response under the strong localized field enhancement of THz metamaterial, establishing a sequential activation dual‐signal output mechanism. Rapid preliminary screening of pathogens is realized via smartphone image recognition by utilizing CeO2−x/Au nanospheres unbound from bacterial surfaces to catalyze colorimetric reactions. Subsequently, the bacteria‐conjugated nanospheres trigger significant changes in the local dielectric environment, leading to distinct frequency shifts that enable precise quantification in THz mode, with limit of detection (LOD) values for common UTI pathogens ranging from 4.58 to 9.31 × 102 CFU/mL. This strategy enables rapid positive/negative discrimination and accurate quantification of bacterial loads in positive samples, achieving outstanding classification (AUC = 0.993) for 75 clinical urine samples. Enabled by CeO2−x/Au composite nanospheres, the dual‐mode platform with affordability (∼$6.8) and time‐efficiency (<1 h) demonstrates potential for UTI diagnosis across diverse scenarios through a tiered approach.