Engineered CpG‐Loaded Nanorobots Drive Autophagy‐Mediated Immunity for TLR9‐Positive Cancer Therapy

Abstract Smart nanorobots have emerged as novel drug delivery platforms in nanomedicine, potentially improving anti‐cancer efficacy and reducing side effects. In this study, an intelligent tumor microenvironment‐responsive nanorobot is developed that effectively delivers CpG payloads to Toll‐like receptor 9 (TLR9)‐positive tumors to induce autophagy‐mediated cell death for immunotherapy. The nanorobots are fabricated by co‐self‐assembly of two amphiphilic triblock polymer peptides: one containing the matrix metallopeptidase 2 (MMP2)‐cleaved GPLGVRGS motif to control the mechanical opening of the nanorobots and provide targeting capability for TLR‐9‐positive tumors and the other consisting of an arginine‐rich GRRRDRGRS sequence that can condense nuclear acid payloads through electrostatic interactions. Using multiple tumor‐bearing mouse models, it is investigated whether the intravenous injection of CpG‐loaded nanorobots could effectively deliver CpG payloads to TLR‐9‐positive tumors and elicit anti‐tumor immunity through TLR9 signaling and autophagy. Therefore, besides being a commonly used adjuvant for tumor vaccination, CpG‐loaded nanorobots can effectively reprogram the tumor immunosuppressive microenvironment and suppress tumor growth and recurrence. This nanorobot‐based CpG immunotherapy can be considered a feasible approach to induce anti‐tumor immunity, showing great therapeutic potential for the future treatment of TLR9‐positive cancers.