Doping-engineered nanosystem for enhancing the antibacterial efficiency of scaffolds through synergistic aSDT and CDT

The BTOM nanosystem was successfully constructed via doping engineering. • The BTOM nanosystem were uniformly distributed with PLLA to fabricate porous scaffolds by SLS. • A tandem sonodynamic and chemodynamic antibacterial system is triggered by US. • The BTOM nanosystem enhanced the antibacterial rates and bone repair of scaffold. Bioactive scaffolds implemented in bone defect remediation are chronically threatened by implant-associated infections (IAIs), which routinely culminate in osteogenesis failure. Developing bioactive implants possessing robust anti-infection capabilities remains a premier yet elusive goal in orthopedic surgery. Herein, doping-engineered manganese-doped barium titanate nanoparticles (BTOM NPs) were synthesized as high-performance piezocatalytic sonosensitizers, which were incorporated with poly-L-lactic acid (PLLA) to fabricate porous scaffolds via selective laser sintering. Mn doping induced local symmetry breaking, enriched oxygen-vacancy-related defects, and substantial lattice distortion, resulting in a 3.17-fold enhancement of the effective piezoelectric coefficient. Under ultrasound (US) irradiation, the modulated band structure and acoustic-field-induced piezopotential promoted charge-carrier separation and enhanced reactive oxygen species (ROS) generation. Specifically, the separated charge carriers promoted interfacial redox reactions involving dissolved oxygen and water, resulting in H 2 O 2 generation. Moreover, the electron-rich defect sites facilitated Mn 2+ /Mn 3+ redox conversion and promoted the Fenton-like activation of piezocatalytically generated H 2 O 2 to form •OH. Benefiting from the coupled antimicrobial sonodynamic therapy (aSDT) and chemodynamic therapy (CDT) process, the PLLA/BTOM scaffolds achieved antibacterial efficiencies of 96.4% against E. coli and 97.3% against S. aureus , accompanied by membrane wrinkling and structural disruption. Moreover, the PLLA/BTOM scaffolds promoted osteogenic differentiation of BMMSCs under low-intensity ultrasound stimulation. Overall, the scaffolds demonstrated combined in vitro antibacterial and osteogenic potential, supporting their further investigation for infected bone-defect repair. Download: Download high-res image (159KB) Download: Download full-size image