Precise control of the local environment and electronic state of the guest is an important method of controlling catalytic activity and reaction pathways.In this paper,guest Pd NPs were introduced into a series of hos...Precise control of the local environment and electronic state of the guest is an important method of controlling catalytic activity and reaction pathways.In this paper,guest Pd NPs were introduced into a series of host UiO-67 MOFs with different functional ligands and metal nodes,the microenvironment and local electronic structure of Pd is modulated by introducing bipyridine groups and changing metal nodes(Ce_(6)O_(6) or Zr_(6)O_(6)).The bipyridine groups not only promoted the dispersion Pd NPs,but also facilitated electron transfer between Pd and UiO-67 MOFs through the formation of Pd-N bridges.Compared with Zr6 clusters,the tunability and orbital hybridisation of the 4f electronic structure in the Ce_(6) clusters modulate the electronic structure of Pd through the construction of the Ce-O-Pd interfaces.The optimal catalyst Pd/UiO-67(Ce)-bpy presented excellent low-temperature activity towards dicyclopentadiene hydrogenation with a conversion of>99% and a selectivity of>99%(50℃,10 bar).The results show that the synergy of Ce-O-Pd and Pd-N promotes the formation of active Pd^(δ+),which not only enhances the adsorption of H_(2) and electron-rich C=C bonds,but also contributes to the reduction of proton migration distance and improves proton utilization efficiency.These results provide valuable insights for investigating the regulatory role of the host MOFs,the nature of host-guest interactions,and their correlation with catalytic performance.展开更多
Many conventional chemotherapeutics play an immune-modulating effect by inducing immunogenic cell death(ICD)in tumor cells.However,they hardly arouse strong antitumor immune response because the immunosuppressive lymp...Many conventional chemotherapeutics play an immune-modulating effect by inducing immunogenic cell death(ICD)in tumor cells.However,they hardly arouse strong antitumor immune response because the immunosuppressive lymphocytes are present in the tumor microenvironment.These immunosuppressive lymphocytes include regulatory T cells(Tregs)and myeloid-derived suppressor cells(MDSCs).We used a low dose of doxorubicin(DOX)to induce ICD in combination with immune regulator 1-methylDL-tryptophan(1 MT)to suppress indoleamine 2,3-dioxygenase and overcome Treg-and MDSCassociated immune suppression.By co-encapsulation of DOX and 1 MT into a reduction-responsive polypeptide nanogel,the drugs were simultaneously released in the tumor cells and synergistically performed antitumor efficacy.After treatment,recruitment of Tregs and MDSCs was inhibited,and the frequency of tumor-infiltrating CD8+T cells was remarkably enhanced.These results demonstrated that the chemoimmunotherapy strategy effectively suppressed tumor growth without causing evident adverse effects,indicating its great potential in clinical cancer therapy.展开更多
文摘Precise control of the local environment and electronic state of the guest is an important method of controlling catalytic activity and reaction pathways.In this paper,guest Pd NPs were introduced into a series of host UiO-67 MOFs with different functional ligands and metal nodes,the microenvironment and local electronic structure of Pd is modulated by introducing bipyridine groups and changing metal nodes(Ce_(6)O_(6) or Zr_(6)O_(6)).The bipyridine groups not only promoted the dispersion Pd NPs,but also facilitated electron transfer between Pd and UiO-67 MOFs through the formation of Pd-N bridges.Compared with Zr6 clusters,the tunability and orbital hybridisation of the 4f electronic structure in the Ce_(6) clusters modulate the electronic structure of Pd through the construction of the Ce-O-Pd interfaces.The optimal catalyst Pd/UiO-67(Ce)-bpy presented excellent low-temperature activity towards dicyclopentadiene hydrogenation with a conversion of>99% and a selectivity of>99%(50℃,10 bar).The results show that the synergy of Ce-O-Pd and Pd-N promotes the formation of active Pd^(δ+),which not only enhances the adsorption of H_(2) and electron-rich C=C bonds,but also contributes to the reduction of proton migration distance and improves proton utilization efficiency.These results provide valuable insights for investigating the regulatory role of the host MOFs,the nature of host-guest interactions,and their correlation with catalytic performance.
基金supported by the National Natural Science Foundation of China(51973216,51873207,51803006,51833010,51673190,and 51603204)the Science and Technology Development Program of Jilin Province(20200404182YY)+1 种基金the Youth Talents Promotion Project of Jilin Province(181909)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2019005)。
文摘Many conventional chemotherapeutics play an immune-modulating effect by inducing immunogenic cell death(ICD)in tumor cells.However,they hardly arouse strong antitumor immune response because the immunosuppressive lymphocytes are present in the tumor microenvironment.These immunosuppressive lymphocytes include regulatory T cells(Tregs)and myeloid-derived suppressor cells(MDSCs).We used a low dose of doxorubicin(DOX)to induce ICD in combination with immune regulator 1-methylDL-tryptophan(1 MT)to suppress indoleamine 2,3-dioxygenase and overcome Treg-and MDSCassociated immune suppression.By co-encapsulation of DOX and 1 MT into a reduction-responsive polypeptide nanogel,the drugs were simultaneously released in the tumor cells and synergistically performed antitumor efficacy.After treatment,recruitment of Tregs and MDSCs was inhibited,and the frequency of tumor-infiltrating CD8+T cells was remarkably enhanced.These results demonstrated that the chemoimmunotherapy strategy effectively suppressed tumor growth without causing evident adverse effects,indicating its great potential in clinical cancer therapy.
