Sonodynamic responsive piezoelectric BiOCl@ag hyaluronic acid hydrogel for septic arthritis with quick cleaning and long-term repair.

Septic arthritis is a severe and rapidly progressive disease that can lead to irreversible joint disorder. Owing to the deep-seated lesions and poor blood circulation, conventional antibiotic therapy for septic arthritis presents several limitations, including prolonged treatment duration, risk of antibiotic resistance, and difficulty in preventing cartilage damage. In this work, we developed BiOCl@Ag@Arg@HA (BAAH) hydrogel combining with ultrasound (US) for septic arthritis treatment. Notably, this study represents the first application of the piezoelectric material BiOCl@Ag in conjunction with US for this purpose. The reactive oxygen species (ROS) generated by BiOCl@Ag under US, together with Ag+, achieved rapid bacterial elimination and sustained antimicrobial activity. Arginine (Arg) scavenges excess ROS and produces nitric oxide (NO) within the system, thereby modulating the inflammatory microenvironment. The lubricating effect of hyaluronic acid (HA) in the articular cavity helps protect chondrocytes. In vitro and in vivo experiments showed that this therapy not only achieved a rapid, deep, in situ, broad-spectrum, and long-lasting antibacterial effect, but also mitigated the risk of antibiotic resistance, regulated the inflammatory microenvironment and protected chondrocytes, finally facilitated the repair of septic arthritis.