Nanoparticles assemble at the interface between two fluids into disordered, liquid-like arrays where the nanoparticles can diffuse laterally at the interface. Using nanoparticles dispersed in water and amine end-capped polymers in oil, nanoparticle surfactants are generated in situ at the interface overcoming the inherent weak forces governing the interfacial adsorption of nanoparticles. When the shape of the liquid domain is deformed by an external field, the surface area increases and more nanoparticles adsorb to the interface. Upon releasing the field, the interfacial area decreases, jamming the nanoparticle surfactants and arresting further shape change. The jammed nanoparticles remain disordered and liquid-like, enabling multiple, consecutive deformation and jamming events. Further stabilization is realized by replacing monofunctional ligands with difunctional versions that cross-link the assemblies. The ability to generate and stabilize liquids with a prescribed shape poses opportunities for reactive liquid systems, packaging, delivery, and storage.

Microbial electrosynthesis is a promising strategy for the microbial conversion of carbon dioxide to transportation fuels and other organic commodities, but optimization of this process is required for commercialization. Cathodes which enhance electrode-microbe electron transfer might improve rates of product formation. To evaluate this possibility, biofilms of Sporomusa ovata, which are effective in acetate electrosynthesis, were grown on a range of cathode materials and acetate production was monitored over time. Modifications of carbon cloth that resulted in a positive-charge enhanced microbial electrosynthesis. Functionalization with chitosan or cyanuric chloride increased acetate production rates 6-7 fold and modification with 3-aminopropyltriethoxysilane gave rates 3-fold higher than untreated controls. A 3-fold increase in electrosynthesis over untreated carbon cloth cathodes was also achieved with polyaniline cathodes. However, not all strategies to provide positively charged surfaces were successful, as treatment of carbon cloth with melamine or ammonia gas did not stimulate acetate electrosynthesis. Treating carbon cloth with metal, in particular gold, palladium, or nickel nanoparticles, also promoted electrosynthesis, yielding electrosynthesis rates that were 6-, 4.7-or 4.5-fold faster than the untreated control, respectively. Cathodes comprised of cotton or polyester fabric treated with carbon nanotubes yielded cathodes that supported acetate electrosynthesis rates that were $3-fold higher than carbon cloth controls. Recovery of electrons consumed in acetate was $80% for all materials. The results demonstrate that one approach to increase rates of carbon dioxide reduction in microbial electrosynthesis is to modify cathode surfaces to improve microbe-electrode interactions. Broader contextMicrobial electrosynthesis is a recently conceived bioenergy strategy in which microorganisms use electrons derived from electrodes to reduce carbon dioxide to organic products that are excreted from the cells. Any form of electrical energy can power microbial electrosynthesis, but when electricity is obtained from solar technologies and water is the source of electrons, microbial electrosynthesis is an articial form of photosynthesis with many potential advantages over biomassbased energy strategies. This study demonstrates that there are several strategies for modifying cathode surface properties that can enhance rates of microbial electrosynthesis.

Through pH-tuning of electrostatic interactions between polymer ligands and nanoparticles at structured-liquid interfaces, liquid droplets can be directed between a jammed nonequilibrium state and a dynamic reconfigurable state. The nanoparticle-surfactant dynamics highly depend on the pH, so that the liquids can be structured using an external field and under variation of pH, or alternatively being realized by remote photo-triggering.

Microbial electrosynthesis cells (MECs) are devices wherein microorganisms can electrochemically interact with electrodes, directly donating or accepting electrons from electrode surfaces. Here, we developed a novel cathode by using nickel nanowires anchored to graphite for the improvement of microbial-catalyzed reduction in MEC cathode chamber. This porous nickel-nanowire-network-coated graphite electrode increased the interfacial area and interfacial interactions between the cathode surface and the microbial biofilm. A 2.3 fold increase in bio-reduction rate over the untreated graphite was observed. Around 282 mM day(-1) m(-2) of acetate resulting from the bio-reduction of carbon dioxide by Sporomusa was produced with 82 ± 14% of the electrons consumed being recovered in acetate.

Nanoring materials with multiple functionalities have attracted significant attention owing to their potential applications in optical and electronic resonators, biological and chemical sensors, molecular imaging, and gene delivery. [1] Recently, several approaches have been proposed for fabricating nanoring materials, including synthesis of silver nanorings prepared from a one-pot procedure, [2] Au and Ag nanorings fabricated using the outer profile of silica nanoparticles as template, [3] and mesoscopic rings prepared by a method based on capillary force in the colloidal crystal. [4] Also, many interesting and unique properties of nanoring materials have been observed; for example, the toroidal structure of packed DNA is natures most efficient morphology for transporting genetic information, done particularly well by viruses. Some researchers want to mimic this process by condensing DNA into a nanoring morphology to improve the effect of gene therapy. The DNA nanoring packed in viruses is multifunctional, but the nanoring materials fabricated to date are limited by a lack of the multiple functionalities. Thus, the preparation of nanoring materials with multiple functionalities of stimuliresponsiveness, biocompatibility, biodegradability, and photoluminescence will be very attractive.[5] We report herein an easy approach to fabricating multifunctional nanorings by the assembly of DNA with a novel multifunctional hyperbranched macromolecule.It has been reported that multivalent cations can condense DNA into nanorings under suitable conditions. [1a,c,i] To prepare nanorings with multiple functionalities of stimuli-responsiveness, biodegradability, and photoluminescence, multivalent cations having these functionalities are prepared first and then used to condense plasmid DNA. Hyperbranched macromolecules are a special kind of macromolecule with three-dimensional structure. It is very easy to incorporate different functionalities into a single molecule of this type. [6,7] To develop photoluminescent nanorings with multiple functionalities, we prepared a novel disulfide-containing hyperbranched poly(amido amine) (HPAA) by Michael addition polymerization. Note that the syntheses of some linear disulfide-containing poly(amido amine)s have been reported, but these species easily condense plasmid DNA into nanoparticles; therefore, we prepared hyperbranched analogues.The co-polyaddition reaction of 1-(2-aminoethyl)piperazine (AEPZ) with N,N'-cystaminebisacrylamide (CBA) and N,N'-methylenebisacrylamide (MBA; Scheme 1) was employed in the preparation of the HPAA containing a 1:2 molar ratio of the CBA unit to the MBA unit (HPAA12). This synthetic route was chosen for three reasons: 1) The disulfidecontaining HPAA with a 1:0 molar ratio of CBA to MBA (HPAA10) obtained by polyaddition of AEPZ and CBA (at a molar ratio of 1:2) and the disulfide-containing HPAA with a 1:1 molar ratio of CBA to MBA (HPAA11) obtained by polyaddition of AEPZ with CBA and MBA at a 1:2 molar ratio of AEPZ to CBA + MBA are not water-soluble, an...