Smartphone-triggered targeted inactivation of MRSA under SERS monitoring

Silver nanoparticles-based multifunctional agents show tremendous potential for simultaneous imaging and against the methicillin-resistant Staphylococcus aureus (MRSA)-induced superficial infection. However, it is still a challenge to achieve a balance between high precision, high antibacterial efficiency, and biocompatibility. Herein, we present a 4-mercaptophenylboronic acid (4-MPBA)-modified Ag2CO3/Ag2O nano-heterojunctions (AgH@M) that can recognize single MRSA cell by surface-enhanced Raman scattering (SERS) and effectively eradicate MRSA under smartphone irradiation. Moreover, the 4-MPBA molecule acts as triple identities for MRSA targeted binding, SERS tag, and inhibition of excessive release of toxic silver ions for the Raman Imaging guided bacterial treatment. AgH@M simultaneously targeted binding on the surface of bacteria and made full use of the released limited Ag+ into the MRSA, thereby reducing the toxicity to mammalian cells. In addition, the potential antibacterial mechanism involves ROS production from photocatalytic behavior, interference with functional genes of quorum sensing, virulence, biofilm, and ATP-binding cassette transporter. Also, the AgH@M can monitor the residual bacteria in MRSA-infected wounds and keratitis animal models in real-time for at least 7 days by SERS and accomplishes a satisfactory therapeutic effect. This work may provide promising visualized heterojunctions for the targeted eradication of MRSA with a portable light source.