Yuxuan Shao,Dan You,Yuqi Wan,Qingrong Cheng,Zhiquan Pan
The activation capacity of molecular oxygen is an important indicator to evaluate the photocatalytic efficiency of a catalyst. In this paper, MoO3−x nanosheets with oxygen vacancies were deposited on WO3 nanoflowers to form a WOM heterojunction, which improved the photocatalytic performance and molecular oxygen activation ability of the catalyst. This novel WOM heterojunction exhibited excellent photoactivity for degrading rhodamine B (RhB), photocatalytic water splitting ability and molecular oxygen activation ability under sunlight irradiation. Among all the samples, WOM83% could degrade 98% of 30 ppm RhB in 40 min. Meanwhile, WOM83% exhibited the highest hydrogen generation rate (4214.2 μmol h−1 g−1) and the strongest TMB oxidation capacity, and can generate 2.23 μmol of ·O2− in 50 min. The enhanced photocatalytic performance via heterojunction construction may be attributed to these following reasons: (i) higher light absorption achieved by the MoO3−x and WO3 composite; (ii) the matched energy band gap of MoO3−x and WO3 led to higher photogenerated carrier mobility; (iii) MoO3−x with oxygen vacancies as electron traps suppressed the photogenerated carrier recombination; (iv) enhanced molecular oxygen activation ability of the WOM heterojunction, such as the production of ·O2−. The measurements for TMB photo-oxidation and ·O2− showed excellent molecular oxygen activation ability of WOM heterojunctions. Finally, a possible photocatalytic mechanism was proposed. This study provided a viable option for the application of materials with oxygen vacancies to remove pollutants and improve molecular oxygen activation ability.
Wen-Xing Zhang,Ze-Lei Zhou,Qi-Yan Lv,Xiejie Song,Junyang Chen,Chang-Bin Niu,Hui-Fang Cui
Cancer starvation/photothermal combined tumor therapy (CST/PTT) has attracted great interest attributed to their mutual compensation and synergistically enhanced effect. However, the very low O2 supply in the tumor microenvironment (TME) greatly limits the CST efficiency of glucose oxidase (GOx). Additionally, the easy degradation in blood circulation and significant off-target effects are big challenges for clinical applications of the GOx-based CST. In this study, a drug delivery system (DDS) with specific tumor-targeted GOx delivery, near-infrared (NIR) light and TME responsive O2 generation, NIR-responsive glucose consumption, high GOx loading, and efficient NIR photothermia was developed. Positively charged AuNRs@MnO2@SiO2 nanoparticles (named AMS+ NPs) were synthesized. GOx was covalently loaded with a high loading ratio of 36.0%. Finally, a thermosensitive biomimetic hybrid membrane composed of a thermosensitive lipid (TSL) membrane, red blood cell membrane (RBCM), and 4T1 cancer cell membrane (CCM) was coated on the NPs through a double-layer strategy. The AMS+-G@TSL@[RBC-CC-TSL]M NPs consumed 32.7 times glucose at 50 °C as that at 37 °C and generated 4.9 times O2 upon NIR laser irradiation. The thermosensitive biomimetic NPs showed an efficient targeting capability to the homotypic 4T1 cancer cells/tumors accompanied by good biocompatibility, macrophage evading capability, high cancer cell cytotoxicity, and excellent antitumor efficacy. The tumor growth inhibition ratio with NIR laser irradiation reached 92.8%. The AMS+-GOx@TSL@[RBC-CC-TSL]M NPs provide a smart, efficient, safe, PTT/CST combined DDS for highly efficient tumor therapy.
TTIMN NPs prepared based on TTIMN has the function of targeting lipid droplet to induce tumor regression by depleting GSH and inactivating GPX4. Meanwhile, the mode of TTIMN NPs catalyzed the conversion of O 2 −• was also clarified according to in vivo experiments, which indicated it could initiate a series of O 2 −• -mediated bio-catalytic reactions to gain autonomously generated O 2 inside solid tumors. TTIMN NPs sensitized O 2 −• formation even under severe O 2 shortage environment, and a part of it would be converted into highly toxic OH•, subsequently triggering the release of cytochrome c and activating the cascade of the Caspase family that ultimately led to cell apoptosis. Self-generated O 2 inhibited tumor proliferation and metastasis mainly by interfering with HIF-related signaling and downregulating DNA methylation. TTIMN NPs has less systemic toxicity in blood systems and no effect on major organs, and blocked tumor progression by maintaining self-metabolism and immune system stability.
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