Tumor signal amplification and immune decoy strategy using bacterial membrane-coated nanoparticles for immunotherapy

In cancer therapy, tumor cells can diminish their signals through mechanisms such as immune escape, thereby evading recognition and elimination by the immune system. Providing tumor signals to enhance the recognition of tumor sites is considered a crucial approach in cancer treatment. Inspired by the decoy-induced directed feeding of fish, we propose a biomimetic nanoparticle system for tumor signal amplification. This biomimetic system comprises magnetically responsive nanoparticles and immune-inducing bacterial membranes. These designs work together to create a baiting effect at the tumor site, attracting and activating immune cells to attack. It has been demonstrated that the generated nanoparticles have the potential to be targeted and delivered to the tumor site under the influence of an external magnetic field, as demonstrated in preliminary <i>in vitro</i> and <i>in vivo</i> studies. Moreover, the nanoparticles utilize the bacterial membrane and cell membrane-translocated calreticulin to induce an immune response, simulating a decoy mechanism to recruit immune cells. The nanoparticles were proved to be effective in recruiting macrophages and neutrophils and reducing tumor size in animal experiments. These features make the nanoparticles an ideal candidate for treating tumors.