Microenvironment regulation of M-N-C single-atom catalysts towards oxygen reduction reaction

The development of cost-effective,robust,and durable electrocatalysts to replace the expensive Pt-based catalysts towards oxygen reduction reaction(ORR)is the trending frontier research topic in renewable energy and electrocatalysis.Particular attention has been paid to metal-nitrogen-carbon(M-N-C)single atom catalysts(SACs)due to their maximized atom utilization efficiency,biomimetic active site,and distinct electronic structure.More importantly,their catalytic properties can be further tailored by rationally regulating the microenvironment of active sites(i.e.,M-N coordination number,heteroatom doping and substitution.Herein,we present a comprehensive summary of the recent advancement in the microenvironment regulation of MN-C SACs towards improved ORR performance.The coordination environment manipulation regarding central metal and coordinated atoms is first discussed,focusing on the structure-function relationship.Apart from the near-range coordination,longrange substrate modulation including heteroatom doping,defect engineering is discussed as well.Besides,the synergy mechanism of nanoparticles and single atom sites to tune the electron cloud density at the active sites is summarized.Finally,we provide the challenges and outlook of the development of M-N-C SACs.

3D-Printed Scaffolds Promote Angiogenesis by Recruiting Antigen-Specific T Cells

The immune response after implantation is a primary determinant of the tissue-repair effects of threedimensional(3D)-printed scaffolds.Thus,scaffolds that can subtly regulate immune responses may display extraordinary functions.Inspired by the angiogenesis promotion effect of humoral immune response,we covalently combined mesoporous silica micro rod(MSR)/polyethyleneimine(PEI)/ovalbumin(OVA)self-assembled vaccines with 3D-printed calcium phosphate cement(CPC)scaffolds for local antigen-specific immune response activation.With the response activated,antigen-specific CD4+T helper2(Th2)cells can be recruited to promote early angiogenesis.The silicon(Si)ions from MSRs can accelerate osteogenesis,with an adequate blood supply being provided.At room temperature,scaffolds with uniformly interconnected macropores were printed using a self-setting CPC-based printing paste,which promoted the uniform dispersion and structural preservation of functional polysaccharides oxidized hyaluronic acid(OHA)inside.Sustained release of OVA was achieved with MSR/PEI covalently attached to scaffolds rich in aldehyde groups as the vaccine carrier.The vaccine-loaded scaffolds effectively recruited and activated dendritic cells(DCs)for antigen presentation and promoted the osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)in vitro.When embedded subcutaneously in vivo,the vaccine-loaded scaffolds increased the proportion of Th2 cells in the spleen and locally recruited antigenspecific T cells to promote angiogenesis in and around the scaffold.Furthermore,the result in a rat skull defect-repair model indicated that the antigen-specific vaccine-loaded scaffolds promoted the regeneration of vascularized bone.This method may provide a novel concept for patient-specific implant design for angiogenesis promotion.

Microenvironment of Liver Regeneration in Liver Cancer

The occurrence and development of liver cancer are essentially the most serious outcomes of uncontrolled liver regeneration. The progression of liver cancer is inevitably related to the abnormal microenvironment of liver regeneration. The deterioration observed in the microenvironment of liver regeneration is a necessary condition for the occurrence, development and metastasis of cancer. Therefore, the use of a technique to prevent and treat liver cancer via changes in the microenvironment of liver regeneration is a novel strategy. This strategy would be an effective way to delay, prevent or even reverse cancer occurrence, development and metastasis through an improvement in the liver regeneration microenvironment along with the integrated regulation of multiple components, targets, levels, channels and time sequences. In addition, the treatment of ＂tonifying Shen（Kidney） to regulate liver regeneration and repair by affecting stem cells and their microenvironment＂ can regulate ＂the dynamic imbalance between the normal liver regeneration and the abnormal liver regeneration＂; this would improve the microenvironment of liver regeneration, which is also a mechanism by which liver cancer may be prevented or treated.

DKK1 determines organotropism of breast cancer metastasis by regulating microenvironments

Supported by the National Natural Science Foundation of China,a collaborative study by the laboratories of Dr.Hu Guohong(胡国宏)from Shanghai Institutes for Biological Sciences,Chinese Academy of Sciences and Dr.Yang Qifeng(杨其峰)from Shangdong University demonstrates that Dickkopf1(DKK1)

Nanomaterials with dual immunomodulatory functions for synergistic therapy of breast cancer brain metastases

A long-standing paucity of effective therapies results in the poor outcomes of triple-negative breast cancer brain metastases.Immunotherapy has made progress in the treatment of tumors,but limited by the non-immunogenicity of tumors and strong immunosuppressive environment,patients with TNBC brain metastases have not yet benefited from immunotherapy.Dual immunoregulatory strategies with enhanced immune activation and reversal of the immunosuppressive microenvironment provide new therapeutic options for patients.Here,we propose a cocktail-like therapeutic strategy of microenvironment regulation-chemotherapy-immune synergistic sensitization and construct reduction-sensitive immune microenvironment regulation nanomaterials(SIL@T).SIL@T modified with targeting peptide penetrates the BBB and is subsequently internalized into metastatic breast cancer cells,releasing silybin and oxaliplatin responsively in the cells.SIL@T preferentially accumulates at the metastatic site and can significantly prolong the survival period of model animals.Mechanistic studies have shown that SIL@T can effectively induce immunogenic cell death of metastatic cells,activate immune responses and increase infiltration of CD8+T cells.Meanwhile,the activation of STAT3 in the metastatic foci is attenuated and the immunosuppressive microenvironment is reversed.This study demonstrates that SIL@T with dual immunomodulatory functions provides a promising immune synergistic therapy strategy for breast cancer brain metastases.