Infinite Coordination Polymer Polydopamine Nanocomposites Dual-Pathway Multistep Induction of Long-Term Hyperimmunity Combined With Photothermal-Chemo Synergistic Therapy Colorectal Cancer

To improve the long-term therapeutic efficacy of colorectal cancer, we propose a synergistic treatment strategy involving dual-pathway, multistep induction of long-term hyperimmunity combined with photothermal-chemotherapy. To implement this strategy, infinite coordination polymer nanoparticles (SN38-Mn(II)-EGCG ICP NPs) were prepared by coordinating SN38, EGCG, and Mn²⁺. These nanoparticles were then coated with polydopamine (PDA) and grafted with folate-PEG-thiol (FA-PEG-SH) onto their surfaces, producing tumor-targeting folate-modified PDA infinite coordination polymer nanocomposites (ICP@FA-PDA nanocomposites). These nanocomposites exhibit a particle size of 94.9 ± 1.6 nm with a high drug loading capacity (83.3% ± 1.5%), drug release under acidic conditions while maintaining stability in physiological environments. Furthermore, each component within the nanocomposites serves multiple functions. Notably, the incorporation of multiple components triggers a powerful antitumor immune effect and establishes enduring immune memory through a dual-pathway and multistep approach, which is produced with the activation of the cGAS-STING pathway and immunogenic cell death (ICD) by a four-component multistep process. Under a low-dose regimen, this approach induces dual-pathway hyperimmunity effect and generates ultra-long immunological memory, marked by a ninefold increase in CD8⁺ T cell infiltration, a fourfold increase in CD4⁺ T lymphocytes, a fourfold reduction in Treg cells, and a fivefold increase in memory T cells. The remarkable therapy efficacy is achieved by hyperimmunity effect combination of SN38 and EGCG chemotherapy and photothermal therapy. In vivo studies demonstrated that mice treated with ICP@FA-PDA nanocomposites achieved complete eradication of cancer within 21 days, with no recurrence observed within 60 days. These nanocomposites hold significant promise and potential for future clinical translation.