A microwave-programmable abiotic/biotic hybrid system for integrated tumor eradication, immune activation, and bone regeneration

To address the challenges of post-resection tumor recurrence and bone defects in osteosarcoma, we develop a microwave (MW)-responsive abiotic/biotic system by integrating thermoelectric Bi 2 Te 3 /Au nanoparticles and genetically engineered non-pathogenic Escherichia coli (Bi 2 Te 3 /Au@BMP2(+)E.Coli). The heterointerface formed between Bi 2 Te 3 and Au gives rise to phonon scattering and additional electron transport channels. This simultaneously enhances the power factor and reduces thermal conductivity, leading to a 3.3-fold enhancement in thermoelectric performance compared to pristine Bi 2 Te 3 . Under MW irradiation, the heterojunction of Bi 2 Te 3 /Au has a great thermoelectric catalytic effect due to enhanced charge separation efficiency, mediates efficient thermal ablation and reactive oxygen species (ROS) generation, while the BMP2(+)E.Coli with hypoxic tropism can target the osteosarcoma sites and potentiate nonspecific immune activation for potent antitumor performance. For bone defect treatment, low-energy MW stimulation is performed to trigger BMP2 secretion from the BMP2(+)E.Coli to controllably improve the bone restoration. Such MW-responsive thermoelectric abiotic/biotic system offers promising insights for clinical osteosarcoma management.