Multi-Mimic Activities of Co₃O₄ Nanopolyhedrons and Application in Regulating the Content of Intracellular Hydrogen Peroxide/Oxygen

Abstract

Herein, Co 3 O 4 nanopolyhedrons with multi-mimics of peroxidase (POD)-, oxidase (OXD)-, catalase (CAT)-, and glutathione peroxidase (GPx)-like activities were developed and utilized in the application of regulating the level of cellular oxygen and hydrogen peroxide combined with polydopamine (PDA). It was found that the multi-mimic activities can be controlled by pH and the OXD-and POD-like activities were the best when the pH was 4 but became weak under weakly acidic or neutral conditions. Meanwhile, the CAT-like activity was the best under neutral and weakly acidic conditions, and the GPx-like activity was better in neutral conditions than in acidic conditions. According to the high CAT-like activity of Co 3 O 4 nanopolyhedrons under weakly acidic conditions, especially at the tumor cell microenvironment, the Co 3 O 4 nanopolyhedrons can catalytically transform the H 2 O 2 into O 2 without interferences from other mimic activities. After coating with PDA, the Co 3 O 4 @PDA with good biocompatibility and dispersion can also be catalyzed to produce O 2 in the cellular microenvironment with high efficiency. The corresponding H 2 O 2 and O 2 fluorescent probes were used to monitor the process, and the main mechanisms were investigated through fluorescence spectra and confocal fluorescence microscopy. This work not only verifies the multi-enzyme properties of Co 3 O 4 nanopolyhedrons but also provides a nanomaterial for the regulation of the content of H 2 O 2 or O 2 in cells by utilizing the CAT-like enzyme property of the nanomaterial. It is considered that the concentration variation of the active small molecules in the cell microenvironment regulated by nanoenzymes may provide some basis for cancer diagnosis and treatment. KEYWORDS: multi-mimetic enzyme properties, Co 3 O 4 nanopolyhedrons, CAT-like activity, content regulation of O 2 , fluorescent probe

Self-Supplying of Hydrogen Peroxide/Oxygen Based on CaO2-Co3O4 Cascade Nanoreactors for Cellular Microenvironment Regulation

“…Co 3 O 4 nanopolyhedrons were synthesized by the coprecipitation method according to our previous research . To prepare CaO 2 -Co 3 O 4 @HA nanoparticles, 0.6 mL of 1 mg·L –1 Co 3 O 4 nanopolyhedron (dissolved with DMF) was first added to 10 mL of ethanol solution containing 0.5 mg·L –1 CaO 2 while simultaneously applying ultrasound.…”

“…The high CAT-like activity of Co 3 O 4 nanopolyhedrons cannot be affected by interferences from other mimic activities. This provides a good opportunity for utilizing them in the construction of a tandem nanoreactor that regulates the levels of reactive oxygen species in the cellular microenvironment . Therefore, based on the self-supplying hydrogen peroxide of MO 2 and the CAT-like activity of Co 3 O 4 nanopolyhedrons, a nanoplatform can be constructed to regulate the contents of H 2 O 2 and O 2 in cells, which may provide a practical strategy for reducing oxidative stress and alleviating tumor hypoxia …”

Construction of Cu/ZIF-67/Prussian Blue Nanostructures with Photothermal-Enhanced Multizyme Activity for Cancer Therapy

“…Compared with normal cells, cancer cells produce an excessive amount of H 2 O 2 , and it is attractive to use catalase (CAT) as an enzyme to generate oxygen in situ. With the development of research, nanozymes that mimic the catalytic reaction of natural enzymes have been applied to the catalytic treatment of tumors. − …”

Hollow Nanooxidase Enhanced Phototherapy Against Solid Tumors

“…40−43 In contrast, CoSn(OH) 6 @CoOOH exhibits oxidase activity and can directly catalyze oxygen to generate with peroxidase-, oxidase-, catalase-and glutathione peroxidase-like activities and applied them to regulate the levels of cellular oxygen and hydrogen peroxide combined with polydopamine. 45 Compared with these oxide enzymes, CoSn-(OH) 6 @CoOOH has a unique porous hollow structure, which makes it suitable for drug loading. As a cyanine dye drug, ICG was loaded into the interior of CoSn(OH) 6 @CoOOH to achieve photothermal and photodynamic effects under nearinfrared laser irradiation, and photothermal stability was significantly enhanced.…”

“…The synergistic generation of ROS and reactive nitrogen species can destroy the intratumoral redox balance and promote cancer cell inhibition . Liu et al constructed Co 3 O 4 nanopolyhedrons with peroxidase-, oxidase-, catalase- and glutathione peroxidase-like activities and applied them to regulate the levels of cellular oxygen and hydrogen peroxide combined with polydopamine . Compared with these oxide enzymes, CoSn­(OH) 6 @CoOOH has a unique porous hollow structure, which makes it suitable for drug loading.…”