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, O 2 and reactive oxygen species (ROS) generation, and innate immune agonist co-delivery to support staged, local multimodal therapy. Monodispersed Au@GelMA microspheres prepared via 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 H 2 O 2 to generate O 2, produced free radical signals and increased pro-inflammatory cytokines secretion in vitro . 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. • A nano-in-micro c-di-AMP@PM@Au@GelMA microsphere depot was developed for triple negative breast cancer local comprehensive intervention. • The fabricated depots integrate electrical conductivity tuning, controllable photothermal effect, oxygen generation, ROS amplification, and innate immune activation. • Microsphere depot-based multimodal local regimen significantly inhibited tumor regrowth and prolonged survival while stabilizing body weight in vivo .