In-doped ZnO nanofibers with Acharia stimulea-inspired morphology: a promising sensing platform for highly rapid and sensitive detection of the Listeria biomarker 3-hydroxy-2-butanone

Abstract

Rapid and sensitive detection of Listeria monocytogenes, a hazardous foodborne pathogen, is still a great challenge in food safety monitoring. Herein, we report the design and fabrication of Acharia stimulea-like In-doped ZnO nanofibers via a simple electrospinning-calcination process for highly sensitive sensing towards 3-hydroxy-2-butanone (3H-2B), a key biomarker produced by Listeria monocytogenes. Synergetic combination of In-doping and morphological engineering greatly enhances the gas-sensing performance. In-doping creates abundant oxygen vacancies and free carriers whereas the unique nanofiber structure ensures maximum exposure of active sites and fast gas diffusion. The optimized 3% In–ZnO sensor exhibits an exceptional response of 830 toward 100 ppm 3H-2B at 170 °C, with an ultra-fast response/recovery time of 1/5 s and a low detection limit of 26.2 ppb. The grain size of the 3% In–ZnO sample is tuned close to twice the Debye length, enabling full electron depletion and optimal sensing behavior. More importantly, a multi-parameter intelligent sensing system is designed for real-time and on-site 3H-2B detection. This study not only establishes In-doped ZnO nanofibers as a superior sensing platform for Listeria but also opens a new avenue for the detection of foodborne pathogens.