Nano-in-Micro GelMA depots assist electro-thermal-immuno orchestral treatment for solid triple negative breast tumor

Triple-negative breast cancer (TNBC) exhibits high local-recurrence risk despite modern systemic therapy assisted with surgery or irradiation therapy. Here, we report an injectable nano-in-micro microsphere depot (cPAG) that integrates conductivity enhancement, photothermal conversion, O₂ and reactive oxygen species (ROS) generation, and innate immune agonist co-delivery to support staged, local multimodal therapy. Monodispersed Au@GelMA microspheres prepared <i>via</i> microfluidics and photocrosslinking reduced high electrostatic resistance of GelMA hydrogels and provided stable 808 nm laser-responsive heating. The porous surface possessed abundant electrostatic adsorption sites for loading MnO_x nanoflowers and anionic stimulator of interferon genes (STING) agonist. MnO_x nanoflowers catalyzed H₂O₂ to generate O_2, produced free radical signals and increased pro-inflammatory cytokines secretion <i>in vitro</i>. Co-delivery of agonist and MnO_x nanoparticles further increased interferon-β secretion, consistent with induction of type I interferon response. In a 4T1 residual-tumor model established by partial tumor resection, a staged regimen consisting of cPAG-assisted irreversible electroporation followed by cPAG-mediated photothermal therapy showed the strongest suppression of local tumor regrowth among tested groups, with maintained body weight during the study window. Overall, cPAG provides a modular nano-in-micro depot strategy to integrate multiple local treatments for postoperative control of TNBC tumor.