A nanozyme-based dual-mode sensor for photoelectrochemical and colorimetric assay of Listeria monocytogenes.

Listeria monocytogenes (L. monocytogenes) is an important food-borne pathogen that causes a disease known as listeriosis in humans and animals. Conventional detection methods and modern molecular techniques are time-consuming and costly. The aim of this study was to develop a sensitive, cost-effective and reliable platform for detecting L. monocytogenes. Herein, a novel TiO2-Fe-N-C nanozyme was successfully synthesized by depositing hemin chloride onto TiO2/g-C3N4. The prepared nanozyme exhibited exceptional peroxidase (POD)-mimic catalytic activity and photocatalytic performance. Meanwhile, a nanozyme-based photoelectrochemical-colorimetric dual-mode sensor was constructed. In the presence of target L. monocytogenes, the TiO2-Fe-N-C nanozyme-based dual-mode system demonstrated wide liner range from 10 to 107 with low detectable limit of 1.33 CFU·mL-1 in PEC and 3.20 CFU·mL-1 in colorimetric, respectively. Its successful application to pork samples, with mutually validated dual-mode detection results, further confirmed high accuracy and practical reliability of this sensing system.