Defect-Rich Ni-CoO@PEG Porous Hexagonal Nanosheets: Multi-enzyme and Ultrasound Catalysis for Synergistic Anticancer Treatment.

Given the similarity with photocatalysis, sonodynamic therapy (SDT) can be defined as ultrasonic (US) catalysis. Encouraged by the principles of photocatalysis and defect chemistry, defect-rich nickel (Ni)-doped cobaltous oxide (Ni-CoO@PEG) porous hexagonal nanosheets have been synthesized as a sonosensitizer. The doping of Ni decreases the band gap that is testified by density functional theory to increase the US-generated charges. Under US irradiation, Ni-CoO@PEG nanosheets produce 1O2 as an active species that is determined by dissolved O2 and electrons. Moreover, the doping also brings abundant oxygen vacancies (OV) that not only are in favor of efficient separation of electron-hole but also enhance the interaction toward O2, boosting 1O2 generation. In addition, Ni-CoO@PEG shows robust mimic catalase (CAT) and peroxidase characterization to effectively improve the intratumor O2 content and oxidation stress. What is more, the nanosheets also possess glucose oxidase activity that can consume glucose to elevate the H2O2/acid level and to block the intracellular energy supply. The tandem nanozyme behaviors would further regulate the tumor microenvironment for assisting anticancer treatment. It is noted that Ni-CoO@PEG reveals a novel half-metallic feature endowing great magnetism and magnetic resonance imaging capacity. The above synergistic treatments exhibit outstanding anticancer performance that also evokes antitumor immunity to suppress metastasis and recurrence, efficiently.