Interfacial Assembly and Jamming of Soft Nanoparticle Surfactants into Colloidosomes and Structured Liquids.

Nanoparticle surfactant (NPS) offers a powerful strategy to generate all-liquid constructs that integrate the inherent properties of the NPs into 3D architectures. Here, using the co-assembly of fluorescent polymeric nanoparticles and amine-functionalized polyhedral oligomeric silsesquioxane, the assembly and jamming behavior of a new type of NPS at the oil-water interface is uncovered. Unlike "solid" inorganic nanoparticles, "soft" polymeric nanoparticles can reorganize when jammed, leading to a relaxation and deformation of the interfacial assemblies, for example, the 3D printed sugar-coated haw stick-like liquid tubules. With NPS serving as emulsifiers, stable Pickering emulsions are prepared that can be converted into robust colloidosomes with pH responsiveness, showing numerous potential applications for encapsulation and controlled release.

The Assembly and Jamming of Nanoparticle Surfactants at Liquid-Liquid Interfaces.

Using the interactions between nanoparticles (NPs) and polymeric ligands to generate nanoparticle surfactants (NPSs) at the liquid-liquid interface, the binding energy of the NP to the interface can be significantly increased, irreversibly binding the NPSs to the interface. By designing a simplified NPS model, where the NP size can be precisely controlled and the characteristic fluorescence of the NPs be used as a direct probe of their spatial distribution, we provide new insights into the attachment mechanism of NPSs at the liquid-liquid interface. We find that the binding energy of NPSs to the interface can be reduced by competitive ligands, resulting in the dissociation and disassembly of NPSs at the interface, and allowing the construction of responsive, reconfigurable all-liquid systems. Smaller NPSs that are loosely packed (unjammed) and irreversibly bound to the interface can be displaced by larger NPSs, giving rise to a size-dependent assembly of NPSs at the interface. However, when the smaller size NPSs are densely packed and jam at the interface, the size-dependent assembly of NPSs at the interface can be completely suppressed.

Molecular Brush Surfactants: Versatile Emulsifiers for Stabilizing and Structuring Liquids.

Using amphiphilic molecular brushes to stabilize emulsions usually requires the synthesis of specific side chains, which can be a time-consuming and difficult challenge to meet. By taking advantage of the electrostatic interactions between water-soluble molecular brushes and oil-soluble oligomeric ligands, the in situ formation, assembly and jamming of molecular brush surfactants (MBSs) at the oil-water interface is described. With MBSs, stable emulsions including o/w, w/o and o/w/o can be easily prepared by varying the molar ratios of the molecular brushes to the ligands. Moreover, when jammed, the binding energy of MBSs at the interface is sufficiently strong to allow the stabilization of liquids in nonequilibrium shapes, i.e., structuring liquids, producing an elastic film at the interface with exceptional mechanical properties. These structured liquids have numerous potential applications, including chemical biphasic reactions, liquid electronics, and all-liquid biomimetic system.

miR-30 promotes thermogenesis and the development of beige fat by targeting RIP140.

Members of the microRNA (miR)-30 family have been reported to promote adipogenesis and inhibit osteogenesis, yet their role in the regulation of thermogenesis remains unknown. In this study, we show that miR-30b/c concentrations are greatly increased during adipocyte differentiation and are stimulated by cold exposure or the ß-adrenergic receptor activator. Overexpression and knockdown of miR-30b and -30c induced and suppressed, respectively, the expression of thermogenic genes such as UCP1 and Cidea in brown adipocytes. Forced expression of miR-30b/c also significantly increased thermogenic gene expression and mitochondrial respiration in primary adipocytes derived from subcutaneous white adipose tissue, demonstrating a promoting effect of miRNAs on the development of beige fat. In addition, knockdown of miR-30b/c repressed UCP1 expression in brown adipose tissue in vivo. miR-30b/c targets the 3'-untranslated region of the receptor-interacting protein 140 (RIP140), and overexpression of miR-30b/c significantly reduced RIP140 expression. Consistent with RIP140 as a target of miR-30b/c in regulating thermogenic gene expression, overexpression of RIP140 greatly suppressed the promoting effect of miR-30b/c on the expression of UCP1 and Cidea in brown adipocytes. Taken together, the data from our study identify miR-30b/c as a key regulator of thermogenesis and uncover a new mechanism underlying the regulation of brown adipose tissue function and the development of beige fat.