No abstract

Tumor hypoxic microenvironment can reduce the therapeutic effects of chemotherapy, radiotherapy, photodynamic therapy, immunotherapy, etc. It is also a potential source of tumor recurrence and metastasis. A biomimetic nanosystem based on zeolitic imidazolate framework 8 (ZIF8), which had multifunctions of hypoxia relief, chemotherapy, and photothermal therapy, was established to improve tumor hypoxic microenvironment and overcome the corresponding therapeutic resistance. ZIF8 enveloped with DOX and CuS nanoparticles (DC@ZIF8) was synthesized by a sedimentation method. Red blood cell membrane and catalase (CAT) were coated onto DC@ZIF8 and biomimetic nanosystem (DC@ZIF8-MEMC) was formed. The designed DC@ZIF8-MEMC had a shape of polyhedron with an average particle size around 254 nm. The loading content of DOX, CAT, and CuS was 4.9%, 6.2%, and 2.5%, separately. The release of DOX from DC@ZIF8-MEMC was pH dependent and significantly faster at pH 5 due to the degradation of ZIF8. DC@ZIF8-MEMC exhibited outstanding photothermal conversion properties and excellent antitumor effect in vitro and in vivo. Moreover, the hypoxia relief by CAT was proved to have good sensitization effect on chemo-photothermal combined therapy. DC@ZIF8-MEMC is a prospective nanosystem, which can realize great chemo-photothermal synergistic antitumor effect under the sensitization of CAT. The biomimetic multifunctional nanoplatform provides a potential strategy of chemo-photothermal synergistic antitumor effect under the sensitization of CAT.

TiO2/SBA-15 and AgCl loaded on TiO2/SBA-15(AgCl-TiO2/SBA-15) composites were synthesized by a facile method. All products were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and N2adsorption-desorption analysis. Photocatalytic activities of the composites were assessed by the photocatalytic decomposition of methyl orange (MO). The results indicated that TiO2or TiO2-AgCl existed in the matrix SBA-15, which reduced the specific surface area, pore volume and pore size of the matrix. The photocatalytic performances of TiO2/SBA-15 were higher than that of pure TiO2, and the resultant AgCl-TiO2/SBA-15 composites showed much higher photocatalytic performances than TiO2/SBA-15.