Lattice-distorted two-dimensional Zr-based metal-organic frameworks for enhanced piezocatalytic-immunotherapy

The low catalytic efficiency of piezoelectric materials is a core limitation of piezocatalytic therapy. This study employed a dimensional engineering strategy to construct a two-dimensional (2D) zirconium-based metal-organic framework (U67-2D) with lattice distortion-enhanced piezoelectric properties for ultrasound-responsive tumor piezocatalytic immunotherapy. Structural analysis revealed that lattice distortion within the 2D structure significantly enhanced the piezoelectric polarization effect by reducing material symmetry, thereby improving charge carrier separation efficiency and boosting reactive oxygen species (ROS) generation efficiency. Mechanistic studies demonstrated that the piezoelectric field-induced band bending enhanced the redox capability of U67-2D, driving ROS production, which induced mitochondrial oxidative damage and immunogenic cell death (ICD). Damage-associated molecular patterns (DAMPs) released by dying tumor cells activated dendritic cell maturation and promoted cytotoxic T lymphocyte infiltration, effectively reversing the immunosuppressive microenvironment and eliciting systemic anti-tumor immunity. This work elucidated the relationship between lattice symmetry-breaking effects and piezocatalytic efficiency, providing a strategy to enhance piezocatalytic therapeutic efficacy.