Engineering a TME-Responsive Hollow ZnzMnx-zOy-Based Nanoplatform for Cancer Theranostic Applications

In this study, a tumor microenvironment (TME)-responsive theranostic nanosystem was engineered by employing hollow zinc-doped manganese oxide (H-Zn_zMn_x-zO_y) nanostructures. Doping Zn²⁺ ions into the Mn_xO_y matrix induces lattice distortion, increases microstrain, and improves surface heterogeneity, thereby enhancing drug-loading capacity and catalytic performance. Meanwhile, optimization of the nanoplatform at Z = 0.05 yielded a high specific surface area (S_BET = 49.11 m² g^-1) and a mesoporous structure. Furthermore, the surface was modified using chitosan cross-linked with tripolyphosphate (Chi-TPP) to enhance biocompatibility and colloidal stability under physiological conditions. Adsorption studies revealed a maximum PTX loading capacity of 151.069 mg g^-1 under the optimal conditions (160 ppm PTX, 0.9 mg mL^-1 nanoplatform, and 7 h contact time), with a loading efficiency of 89.7%. The in …