Bifunctional Piezo-Enhanced PLLA/ZA Coating Prevents Aseptic Loosening of Bone Implants

Prevention of aseptic loosening, the main reason for secondary surgery of bone implants, is of great crucial clinical importance. As a promising bioactive material to promote bone regeneration, the piezoelectric materials for preventing aseptic loosening has not been reported. Here, a surface coating is presented for implants based on piezoelectric poly(L-lactic acid) (PLLA). The coating ingeniously utilizes zoledronic acid (ZA), a drug used to treat osteoporosis, as a nucleating agent to enhance the piezoelectricity of PLLA. The coating can not only provide a continuous porous piezoelectric environment to stimulate osteogenic differentiation without intervention, but also effectively inhibit the osteolytic activity of osteoclasts through the slow release of ZA, achieving long-term effectiveness with a single implantation. The rat femur cavity implantation experiment suggests that, the PLLA/ZA coating can rapidly initiate osseointegration of the implant and effectively mitigate the risk of aseptic loosening, even in the presence of metal submicroscopic particles that induce aseptic loosening. This strategy of piezo-enhanced PLLA drug-loaded coating may provide a new idea for the surface modification of bone implants.