A Mechanically Adaptive Titanium Scaffold With a Lattice-Modulated Piezocatalytic Coating for Infection Treatment and Bone Regeneration.

Abstract

Implant-associated infections present a major clinical challenge, as orthopedic implants are required to both suppress bacterial infection and support subsequent bone regeneration. Herein, a mechanically adaptive auxetic titanium scaffold integrated with a lattice-modulated piezocatalytic coating is developed for infected bone repair. A titanium scaffold with a negative Poisson's ratio structure demonstrates uniform stress distribution under compression. It prolongs fluid residence time by creating complex flow paths, which is favorable for interaction with surrounding bone tissue. Additionally, a potassium sodium niobate (KNN) piezoelectric coating with strontium (Sr) incorporated as a lattice dopant is constructed on the scaffold surface. Strontium doping restructures the electromechanical landscape of KNN, amplifying its piezoelectric response and piezocatalytic reactivity, which underpins potent antibacterial efficacy. Concurrently, the osteogenic bioactivity imparted by Sr enables robust osseointegration and bone regeneration. In a rabbit femoral condyle infected bone defect repairment, the piezo-coated auxetic scaffold achieves suppression of local infection and inflammation after 1 week of ultrasound treatment. Subsequently, enhanced osseointegration and bone regeneration are observed, accompanied by improved hindlimb strength and motor coordination. This work establishes a multifunctional implant paradigm that couples mechanical adaptation with lattice-modulated piezocatalysis, enabling synergistic infection eradication and bone regeneration.