A Tremella-like Mesoporous Calcium Silicate Loaded by TiO_(2) with Robust Adsorption and Photocatalytic Degradation Capabilities

A titanium dioxide loaded tremella-like mesoporous calcium silicate hydrate(TiO_(2)@CSH)with both adsorption and photocatalytic degradation activity was successfully prepared by a hydrothermal method combined with sol-gel strategy in two steps in this work.Tremella-shaped CSH provides abundant active sites for accommodating of TiO_(2),thus the corresponding TiO_(2)@CSH achieved a high loading ratio of 36.73%.Such a special shaped TiO_(2)@CSH exhibits excellent pre-enrichment capacity and photocatalytic degradation capacity for organic pollutants.Bisphenol A(BPA)removal experiments show that TiO_(2)@CSH can remove 91.17%of BPA from aqueous solutions.Studies on removal mechanism suggest that BPA tends to bind on the interface between CSH and TiO_(2) and the pre-enrichment process conforms to the intraparticle diffusion model;and then,it is decomposed to harmless substances of CO_(2) and H_(2)O during the photocatalytic process.The experimental results show that loading functional nanoparticles such as TiO_(2) on the surface of inorganic porous materials can endow inert porous materials with new functions such as photocatalytic degradation,which effectively expands the application range of inorganic porous materials.

A collaborative strategy for enhanced reduction of Cr(Ⅵ) by Fe(0) in the presence of oxalate under sunlight:Performance and mechanism

Nanometer-size zero-valent iron(NZVI)is an efficient reducing agent,but its surface is easily passivated with an oxide layer,leading to reaction inefficiency.In our study,oxalate(OA)was introduced into this heterogeneous system of NZVI,which could form ferrioxalate complexes with the NZVI surface-bound Fe3+and dissolved Fe3+in the solution.Photolysis of ferrioxalate complexes can facilitate the generation of Fe2+from Fe3+and CO2·-radical,both species have strong reduction capacity.Hence,a"photo-oxalate-Fe(0)"system through sunlight induction was established,which not only prohibited the formation of a surface passivation layer,but also displayed a synergetic mechanism of ferrioxalate photolysis to enhance reduction,exhibiting remarkably higher degradation activity(several times faster)toward the model pollutant Cr(Ⅵ)than the mechanism with NZVI alone.Factor tests suggested that both NZVI dosage and OA content markedly affected the reduction rate.Low pH was beneficial to the reduction efficiency.Moreover,recyclability experiment showed that the reduction rate decreased from 0.21706 to 0.03977 min-1 after three cycles of reuse due to the NZVI losing reaction activity generally,but the system still maintained considerable reduction capacity.Finally,a mechanism was revealed whereby NZVI would transform to Fe oxides after the exhaustion of its reductive power,and the photolysis of ferrioxalate to promote the cycling of iron species played the predominant role in providing extra reduction ability.These features confirm that introduction of OA into Cr(Ⅵ)reduction by NZVI through sunlight induction is advantageous and promising.

Cancer-cell-biomimetic nanoparticles systemically eliminate hypoxia tumors by synergistic chemotherapy and checkpoint blockade immunotherapy

Checkpoint blockade-based immunotherapy has shown unprecedented effect in cancer treatments,but its clinical implementation has been restricted by the low host antitumor response rate.Recently,chemotherapy is well recognized to activate the immune system during some chemotherapeutics-mediated tumor eradication.The enhancement of immune response during chemotherapy might further improve the therapeutic efficiency through the synergetic mechanism.Herein,a synergistic antitumor platform(designated as BMS/RA@CC-Liposome)was constructed by utilizing CT26 cancer-cell-biomimetic nanoparticles that combined chemotherapeutic drug(RA-V)and PD-1/PD-L1 blockade inhibitor(BMS-202)to remarkably enhance antitumor immunity.In this study,the cyclopeptide RA-V as chemotherapeutic drugs directly killing tumor cells and BMS-202 as anti-PD agents eliciting antitumor immune responses were co-encapsulated in a pH-sensitive nanosystem.To achieve the cell-specific targeting drug delivery,the combination therapy nanosystem was functionalized with cancer cell membrane camouflage.The biomimetic drug delivery system perfectly disguised as endogenous substances,and realized elongated blood circulation due to anti-phagocytosis capability.Moreover,the BMS/RA@CC-Liposome also achieved the selective targeting of CT26 cells by taking advantage of the inherent homologous adhesion property of tumor cells.The in vitro and in vivo experiments revealed that the BMS/RA@CC-Liposome realized PD-1/PD-L1 blockade-induced immune response,RA-V-induced PD-L1 down-regulation and apoptosis in cancer cells.Such a system combining the advantages of chemotherapy and checkpoint blockade-based immunotherapy to create an immunogenic tumor microenvironment systemically,demonstrated improved therapeutic efficacy against hypoxic tumor cells and offers an alternative strategy based on the immunology of the PD-1/PD-L1 pathway.