Yan Lv,Lin Yue,Qian Li,Baoyi Shao,Sen Zhao,Haitao Wang,Shijia Wu,Zhouping Wang
Herein, the design and synthesis of a multifunctional (Fe3O4-NaYF4:Yb,Tm)@TiO2 photocatalyst through a facile sol–gel process combined with electrostatic self-assembly has been reported. Particularly, as an upconversion sensor, NaYF4:Yb,Tm nanoparticles have the ability to convert near-infrared (NIR) light into ultraviolet (UV) emissions, so that the catalytic body TiO2 can indirectly utilize the NIR part of sunlight but not UV light. The excellent photocatalytic activity of the hybrid samples is evaluated using a model of the degradation of methylene blue (MB). Most importantly, the obtained materials exhibit remarkable magnetic properties because of the addition of a magnetic component (Fe3O4), therefore, the photocatalysts possess desired recyclability and reusability, which is significant for actual applications. Finally, the possible photocatalysis mechanism of the nanohybrids is discussed and hydroxyl radicals (OH˙) are confirmed as the main reactive species.
Due to non-invasive deep imaging and therapy, multifunctional agents of magnetic resonance (MR)/upconversion luminescence (UCL) imaging and photodynamic therapy (PDT) play an important role in clinical diagnosis and treatment of cancers, and also in the assessment of therapy effect. In this paper, tetra-sulfonic phthalocyanine aluminium (AlPcS4) photosensitizers-conjugated Fe3O4@NaYF4:Yb/Er (NPs-AlPcS4) nanocomplexes were synthesized for the T2-weighted MR/UCL imaging and PDT of cancer cells. The PEG-coated Fe3O4@NaYF4:Yb/Er nanoparticles (NPs) with a core–shell structure showed strong T2-weighted MR relaxivity (r2 = 42.131 mM−1 s−1) and UCL emission in the visible region (the bands at about 654–674 nm, 545 nm and 524 nm), and were conjugated successfully with AlPcS4 photosensitizer by electrostatic interaction. By direct observation of XFM and staining with Prussian blue, the element distribution and location of NPs in MCF-7 cells were characterized, respectively. Under irradiation from a 980 nm laser, the death ratio of MCF-7 cells incubated with NPs-AlPcS4 nanocomplexes could be up to about 70%. The results indicated that the as-prepared NPs-AlPcS4 nanocomplexes would be a potential candidate as multifunctional nanoprobes for the dual-modal T2-weighted MR/UCL imaging and PDT of cancers in the future.
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