A multifunctional nanoplatform for dual-readout visual detection and real-time inactivation of Staphylococcus aureus with nanozymes and Au nanorods

Abstract

Pathogenic bacteria pose a significant burden on global public health. To ensure food safety and prevent the spread of foodborne diseases, the multifunctional technical platforms for rapid detection and inactivation of pathogens are urgently needed. Herein, a new dual-readout detection and bacterial inactivation nanoplatform was constructed based on K10P2W18Fe4(H2O)2O68@polydopamine (P2W18Fe4@PDA) nanozymes and Au nanorods (AuNRs). The target bacteria such as Staphylococcus aureus (S. aureus) was firstly specifically isolated by the Fe3O4-Apt in complex sample matrices. Then, the isolated bacteria (Fe3O4-Apt-S. aureus) were strongly bound by the P2W18Fe4@PDA nanozymes with excellent peroxidase-like activity and highly efficient photothermal conversion. Accordingly, bacteria can be sensitively detected with monochrome signal catalyzed by the nanozyme (3, 3′, 5, 5′-tetramethylbenzidine (TMB) oxidation) and multicolor signal produced by TMB2+ etching AuNRs. With the assay, as low as 29 CFU/mL S. aureus could be distinguished. Meanwhile, over 99% S. aureus in the magnetic separation can be effectively inactivated by 808 nm Near-infrared (NIR) light within 10 min. Moreover, S. aureus was detected successfully in spiked milk with a recovery rate of 98.64%–109.04% using this method, indicated that the method held significant promise for applications in food analysis and control.