We achieved a tunable Pgo for gas adsorption in a flexible framework by modulating the dynamic rearrangement of coordination bonds of paddle-wheel unit via cobalt substitution.

Developing novel synthetic strategies to downsize metal‐organic frameworks (MOFs) from polydisperse crystals to monodisperse nanoparticles is of great importance for their potential bioapplications. In this work, a novel synthetic strategy termed gelothermal synthesis is proposed, in which coordination polymer gel is first prepared and followed by a thermal reaction to give the monodisperse MOF nanoparticles. This novel synthetic strategy successfully leads to the isolation of Materials of Institute Lavoisier (MIL‐88), Cu(II)‐fumarate MOFs (CufumDMF), and Zeolitic Imidazolate Frameworks (ZIF‐8) nanoparticles. Focused on MIL‐88A, the studies reveal that the size can be well‐tuned from nanoscale to microscale without significant changes in polydispersity index (PDI) even in the case of in situ metal substitution. A possible mechanism is consequently proposed based on extensive studies on the gelothermal condition including sol‐gel chemistry, thermal condition, kinds of solvents, and so on. The unique advantages of monodisperse MIL‐88A nanoparticles over polydisperse ones are further demonstrated in terms of in vitro magnetic resonance imaging (MRI), cellular uptake, and drug‐carrying properties.

Immunomodulation has made remarkable progress in fighting infectious disease and cancer. Conventionally, immunomodulation largely relies on chemical/biochemical agents, which, unfortunately, suffer from sever off-target adverse effects. Recent insights into nano-bio interactions suggest that nanomaterials can directly participate in immunomodulation. A range of physical and chemical cues at the nano-bio interface have been harnessed to regulate diverse immuno-signaling for disease control and treatment. In this Minireview, we summarize recent studies on the physical and chemical cues enabled by intrinsic nanomaterials to trigger immunological signaling. First, we discuss physical cues mediated by surface topography, hydrophobicity, charge, and heat at the nano-bio interface for immunomodulation. Then, various nanomaterials enabled chemical cues, such as metal species and oxidative species are outlined. Finally, our perspectives on challenges and possible future directions are provided.

Nanoscale metal–organic frameworks (nanoMOFs) are emerging as an important class of nanomaterials for the systematical investigation of biomedically relevant structure‐property relationship (SPR) due to their highly tailorable features. In this work, the reticular chemistry approach is shown to explore the SPR of a fcu‐type Zr(IV)‐nanoMOF for T1‐weighted magnetic resonance imaging (MRI). Isoreticular replacement of the eight‐coordinated square‐antiprismatic Zr(IV) by nine‐coordinated Gd(III) brings a stoichiometric water capped on the square‐antiprismatic site, enabling the relaxation transfer in the inner‐sphere, giving the r1 value of 4.55 mM−1·s−1 at the doping ratio of Gd : Zr = 1 : 1. Then, these isoreticular engineering studies provide feasible ways to facilitate the relaxation transfer in the second‐ and outer‐sphere of the Gd(III)‐doped Zr‐oxo cluster for the relaxation respectively. Finally, these in vitro and in vivo MRI studies revealed that the Gd(III)‐doped Zr‐oxo cluster aggregated underlying the fcu‐type framework surpasses its discrete molecular cluster for MRI. These results demonstrated that there is plenty of room inside MOFs for T1‐weighted MRI by reticular chemistry.

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