Pyroelectric Heterojunction Biointerface for Bacterial Eradication and Bone Regeneration

ABSTRACT Although pyroelectric materials are widely used in energy conversion, their biomedical potential‐particularly that of pyroelectric heterojunctions in implant materials‐remains unexplored. Here, a strongly interfacial coupled pyroelectric heterojunction was developed to prevent implant‐associated infections while enhancing osseointegration. The pyroelectric heterojunction is constructed by in situ growth of the conjugated polymer polypyrrole (PPy) onto barium titanate nanorods, in which PPy serves as a localized photothermal transducer and an interfacial charge mediator. Under near‐infrared irradiation, this heterojunction converts confined thermal fluctuations into transient pyroelectric polarization fields directly at the biointerface. The results indicate that the heterojunction‐mediated pyroelectric signals disrupt the electron transport in the bacterial respiratory chain, leading to efficient eradication of E. coli , MRSA, and P. gingivalis with antibacterial rates exceeding 99%. In addition, the built‐in electric field of the pyroelectric heterojunction enhances ATP synthesis and accelerates cellular energy metabolism in BMSCs, markedly promoting osteogenic differentiation. This work establishes a pyroelectric heterojunction‐based biointerface engineering strategy for implantable systems, presenting a versatile and programmable platform for on‐demand biointerface therapy.