A hemoglobin-based nanozyme with ruthenium-induced nanomotor ability exhibiting photothermal and chemodynamic responses

Ruthenium functionalized organometallic nanoparticles (Hb@Ru NPs) ca. 10 nm in size, containing crystalline Ru phases were synthesized by a new, single-stage hydrothermal protocol using hemoglobin (Hb) as the skeleton. Compared to currently reported nanozymes, Ru@Hb NPs demonstrated enhanced catalase- and and peroxidase-mimicking activities, produced superoxide (O₂^•-) and singlet oxygen (¹O₂) radicals and showed significant glutathione depletion. The maximum substrate consumption rates of 107.5 mM mg^-1s^-1 and 6.94 µM mg^-1s^-1, were obtained for catalase-like and peroxidase-like activities, respectively. Hb@Ru NPs exhibited ruthenium induced nanomotor behavior which was utilized to enhance the interaction between tumor cells and nanozyme. Photothermal conversion behavior of Hb@Ru NPs was demonstrated with the temperature elevations of up to 29 °C under NIR laser irradiation. Therapeutic potential of Hb@Ru NPs was evaluated using T98G glioblastoma and HepG2 cells. In-vitro combinatorial photothermal/chemodynamic therapy (PTT&CDT) with T98G cells achieved up to 92.7% cell death, with effective intracellular ROS formation and yielded an apoptotic rate of 63.32%, as determined by flow cytometry. TUNEL staining demonstrated that Hb@Ru NPs significantly induced DNA fragmentation in T98G cells by combined PTT&CDT via producing the most pronounced apoptotic response. PTT&CDT with Hb@Ru NPs also suppressed the migration and proliferation of glioblastoma cells, significantly inhibiting the wound closure in stratch assay.