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 1 O 2 as an active species that is determined by dissolved O 2 and electrons. Moreover, the doping also brings abundant oxygen vacancies (O V ) that not only are in favor of efficient separation of electron–hole but also enhance the interaction toward O 2, boosting 1 O 2 generation. In addition, Ni–CoO@PEG shows robust mimic catalase (CAT) and peroxidase characterization to effectively improve the intratumor O 2 content and oxidation stress. What is more, the nanosheets also possess glucose oxidase activity that can consume glucose to elevate the H 2 O 2 /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.