Carrier-free nanoreshapers disrupt cancer-associated fibroblast barriers and alleviate immunosuppression for synergistically potentiated immunotherapy.

The dense extracellular matrix and immunosuppressive microenvironments create dual physical and immunological barriers that often render immunotherapy ineffective in solid tumors. Herein, by using a one-pot approach, we developed a carrier-free nanoreshaper (QN NP) through coordinating manganese ions (Mn2+) with quercetin (Qc) and the indoleamine 2,3-dioxygenase 1 inhibitor NLG919 to lift these restrictions. Benefiting from uniform size and exceptional stability, QN NPs achieved efficient tumor accumulation, and triggered drug release in response to tumor microenvironment. As active pharmaceutical ingredients, Qc normalizes cancer-associated fibroblasts and reduces extracellular matrix deposition; Mn2+ triggers potent immune responses both by generating hydroxyl radicals to induce immunogenic cell death and by activating the stimulator of interferon genes (STING) pathway; and NLG919 disrupts the tryptophan/kynurenine metabolic pathway to alleviate tumor immunosuppression. Together, the coordinated action overcomes both the physical barrier and immunosuppressive niche, thereby enhancing immune cell infiltration and effector function. Furthermore, combining QN NPs with an anti-PD-L1 antibody generated robust synergistic activity, leading to cooperative suppression of both primary tumor growth and pulmonary metastases. This carrier-free nanoreshaping strategy overcomes the dual challenges of stromal fibrosis and immune evasion, providing a promising paradigm for developing combined immunotherapies based on physical barrier disruption and microenvironment reprogramming.