Yingde Xu, Yifan Wang, Hongwei Bi, Zhonghui Gao, W B Xu, Hui Jiang, Zhenduo Cui, Yanqin Liang, Shengli Zhu, Yufeng Zheng, Shuilin Wu, Zhaoyang Li
The underlying mechanisms by which heterogeneous interfaces enhance piezoelectric catalytic effects under ultrasonic irradiation, along with their potential biomedical applications, remain poorly understood. In this study, a versatile Z-Scheme nanoplatform by encapsulating the BiO 2-x /Ag 3 PO 4 heterojunction within poly(lactic- co -glycolic acid) (PLGA) microspheres (BA@PLGA) was developed for ultrasound-activated deep-lung antibacterial therapy. The Z-scheme heterojunction synergistically integrates piezoelectric and built-in electric fields, achieving 2.2 and 4.7-fold enhancements in piezoelectric ( d 33 ) and electromechanical coupling ( k ) coefficients, respectively. Ultrasonic-induced dynamic modulation of the piezoelectric potential in BiO 2-x /Ag 3 PO 4 generated a “carrier-pumping” effect, which enhanced polarized charge migration efficiency and thereby markedly amplified reactive oxygen species (ROS) production. Consequently, with the assistance of trace Ag +, 99.87 ± 0.05% of methicillin-resistant Staphylococcus aureus (MRSA) were effectively eradicated within 15 min in vitro . Prokaryotic transcriptome analysis further revealed that the synergistic effect of ROS and trace Ag + disrupted the cell envelope and interfered with the core metabolic pathways of MRSA. This ultrasound-activated platform, integrating piezocatalysis and trace Ag +, achieved over 99.9% bacterial clearance rapidly (1.6log superiority over gentamicin) and alleviated inflammation in a MRSA-induced pneumonia, demonstrating considerable potential for combating bacterial infections in deep-seated tissues.