Artificial Macrophage with Hierarchical Nanostructure for Biomimetic Reconstruction of Antitumor Immunity.

Artificial cells are constructed from synthetic materials to imitate the biological functions of natural cells. By virtue of nanoengineering techniques, artificial cells with designed biomimetic functions provide alternatives to natural cells, showing vast potential for biomedical applications. Especially in cancer treatment, the deficiency of immunoactive macrophages results in tumor progression and immune resistance. To overcome the limitation, a BaSO4@ZIF-8/transferrin (TRF) nanomacrophage (NMΦ) is herein constructed as an alternative to immunoactive macrophages. Alike to natural immunoactive macrophages, NMΦ is stably retained in tumors through the specific affinity of TRF to tumor cells. Zn2+ as an "artificial cytokine" is then released from the ZIF-8 layer of NMΦ under tumor microenvironment. Similar as proinflammatory cytokines, Zn2+ can trigger cell anoikis to expose tumor antigens, which are selectively captured by the BaSO4 cavities. Therefore, the hierarchical nanostructure of NMΦs allows them to mediate immunogenic death of tumor cells and subsequent antigen capture for T cell activation to fabricate long-term antitumor immunity. As a proof-of-concept, the NMΦ mimics the biological functions of macrophage, including tumor residence, cytokine release, antigen capture and immune activation, which is hopeful to provide a paradigm for the design and biomedical applications of artificial cells.

MOF-Templated Fabrication of Hollow Co4N@N-Doped Carbon Porous Nanocages with Superior Catalytic Activity.

Metallic Co4N catalysts have been considered as one of the most promising non-noble materials for heterogeneous catalysis because of their high electrical conductivity, great magnetic property, and high intrinsic activity. However, the metastable properties seriously limit their applications for heterogeneous water phase catalysis. In this work, a novel Co-metal-organic framework (MOF)-derived hollow porous nanocages (PNCs) composed of metallic Co4N and N-doped carbon (NC) were synthesized for the first time. This hollow three-dimensional (3D) PNC catalyst was synthesized by taking advantage of Co-MOF as a precursor for fabricating 3D hollow Co3O4@C PNCs, along with the NH3 treatment of Co-oxide frames to promote the in situ conversion of Co-MOF to Co4N@NC PNCs, benefiting from the high intrinsic activity and electron conductivity of the metallic Co4N phase and the good permeability of the hollow porous nanostructure as well as the efficient doping of N into the carbon layer. Besides, the covalent bridge between the active Co4N surface and PNC shells also provides facile pathways for electron and mass transport. The obtained Co4N@NC PNCs exhibit excellent catalytic activity and stability for 4-nitrophenol reduction in terms of low activation energy (Ea = 23.53 kJ mol-1), high turnover frequency (52.01 × 1020 molecule g-1 min-1), and high apparent rate constant (kapp = 2.106 min-1). Furthermore, its magnetic property and stable configuration account for the excellent recyclability of the catalyst. It is hoped that our finding could pave the way for the construction of other hollow transition metal-based nitride@NC PNC catalysts for wide applications.

Marriage of artificial catalase and black phosphorus nanosheets for reinforced photodynamic antitumor therapy.

Two dimensional (2D) semiconducting nanomaterials have shown great potential for antitumor therapy. However, their clinical applications are seriously hampered by the tumour microenvironments. Bearing this in mind, we propose to improve the performance of 2D semiconducting nanomaterials using artificial catalase. In this work, we decorate black phosphorus (BP) nanosheets with Pt nanoparticles (NPs) through an in situ growth strategy. Pt NPs as artificial catalases can efficiently decompose the accumulated H2O2 in tumours to relieve tumour hypoxia, and thereafter improve the photodynamic antitumor activity of BP nanosheets. This work paves a new avenue for the functionalization of 2D semiconducting nanomaterials, which will promote the development of 2D semiconductor based nanodrugs.

NIR light controlled release of caged hydrogen sulfide based on upconversion nanoparticles.

A NIR light induced H2S release platform based on UCNPs was constructed. Under NIR light excitation, UCNPs can emit UV light which triggers H2S release in a spatial and temporal pattern. The platform was also employed to real-time monitor the delivery process in vivo, which may provide a new way for the use of H2S-based therapeutics for a variety of diseases.