A near-infrared/tumor microenvironment dual-responsive cobalt-based material for photothermal/photodynamic/DNA-damaging chemotherapy synergistic therapy and anti-inflammation

The co-ordination properties of biomolecules with metal ions can lead to changes in their structures and functions. This work discloses that cobalt ions (Co2+) can induce structural changes in DNA by coordinating with guanine and inactivate copper/zinc superoxide dismutase (Cu/Zn-SOD) by changing the secondary structure. The Co2+ at high concentrations can suppress cell growth and induce apoptosis. Herein, we fabricate a light and tumor microenvironment (TME) dual-responsive polydopamine-coated cobalt boride (CoB@PDA) as a Co2+-carrying material, NIR-driven photothermal/photodynamic agent, catalase-like nano-enzyme, reactive oxygen species (ROS) moderator, and hydrogen (H2) supplier. CoB@PDA with catalase-like properties can convert the H2O2 at tumor site into O2, ·O2− and 1O2, thus inducing oxidative stress and alleviating tumor hypoxia. Under 808 nm irradiation, CoB@PDA can induce a hyperthermia by photothermal effect and trigger photosensitization of O2 to toxic 1O2, thus achieving the photothermal therapy (PTT) and photodynamic therapy (PDT) actions. Meanwhile, decomposition of CoB@PDA in the acidic TME releases Co2+ to inhibit the growth of residual tumor cells post phototherapy and H2 to suppress the inflammatory response induced by phototherapy. The complete ablation of solid tumors with no side effects and recurrence indicates that CoB@PDA is promising for cancer therapy, and thus it provides valuable insights for the development of multifunctional antineoplastic agents.