The spatial arrangement of plasmonic nanoparticles can dramatically affect their interaction with electromagnetic waves, which offers an effective approach to systematically control their optical properties and manifest new phenomena. To this end, significant efforts were made to develop methodologies by which the assembly structure of metal nanoparticles can be controlled with high precision. Herein, recent advances in bottom-up chemical strategies toward the well-controlled assembly of plasmonic nanoparticles, including multicomponent and multifunctional systems are reviewed. Further, it is discussed how the progress in this area has paved the way toward the construction of smart dynamic nanostructures capable of on-demand, reversible structural changes that alter their properties in a predictable and reproducible manner. Finally, this review provides insight into the challenges, future directions, and perspectives in the field of controlled plasmonic assemblies.

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Here, we report plasmonic metamolecules with dynamically controllable optical magnetism. A dynamic metamolecule (DMM) is constructed by decorating gold or silver nanobeads on a thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel sphere, which generates uniform coresatellite-type assembly structures with an interbead distance, allowing for strong interparticle coupling. Experimental and simulation results revealed strong magnetic dipole and quadrupole modes observable in the far field both for gold and silver DMMs when the temperature was set above the lower critical solution temperature (LCST) of PNIPAM. Interestingly, gold DMMs showed stronger and more pronounced magnetic resonances than silver DMMs, despite the general notion that silver nanostructures possess superior plasmonic properties. The strong magnetic coupling and structural uniformity along with the ability to dynamically control the assembly structure allowed us to probe distinct optical magnetism in gold and silver and experimentally observe magnetic quadrupole in solution-phase metamolecules for the first time.

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T helper (Th) 17 cells are a subset of Th cells expressing interleukin- (IL-) 17 and initiating an inflammatory response in autoimmune diseases. Graft-versus-host disease (GVHD) is an immune inflammatory disease caused by interactions between the adaptive immunity of donor and recipient. The Th17 lineage exhibits proinflammatory activity and is believed to be a central player in GVHD. IL-1 performs a key function in immune responses and induces development of Th17 cells. Here, we show that blockade of IL-1 signaling suppresses Th17 cell differentiation and alleviates GVHD severity. We hypothesized that the IL-1 receptor antagonist (IL-1Ra) would suppress Th17 cell differentiation in vitro via inhibition of glycolysis-related genes. Blockade of IL-1 using IL-1Ra downregulated Th17 cell differentiation, an alloreactive T cell response, and expression of genes of the glycolysis pathway. Severity of GVHD was reduced in mice with a transplant of IL-Ra-treated cells, in comparison with control mice. To clarify the mechanisms via which IL-1Ra exerts the therapeutic effect, we demonstrated in vivo that IL-1Ra decreased the proportion of Th17 cells, increased the proportion of FoxP3-expressing T regulatory (Treg) cells, and inhibited expression of glycolysis-related genes and suppressed Th17 cell development and B-cell activation. These results suggest that blockade of IL-1 signaling ameliorates GVHD via suppression of excessive T cell-related inflammation.