Microwave assisted cross-coupling reactions using palladium nanoparticles in aqueous media

<p>Glucose stabilized palladium nanoparticles (PdNPs) have been prepared and the application of NPs in catalyzing both Suzuki and Heck reactions has been explored in aqueous media under microwave conditions. Both electron-rich and electron-deficient aryl halides can be coupled with a variety of boronic acids and styrene to access a wide variety of biaryl compounds and substituted alkenes in good to excellent yields. The catalyst can be recycled and reused four times with minimally affecting the morphology and efficiency of the nanoparticles. A plausible reaction mechanism has been proposed.</p

Explosive Chrysopoeia

Fulminating gold, the first high-explosive compound to be discovered, disintegrates in a mysterious cloud of purple smoke, the nature of which has been speculated upon since its discovery in 1585. In this work, we show that the colour of the smoke is due to the presence of gold nanoparticles.Comment: 8 pages, 4 figures, 1 tabl

Spontaneous assembly of chemically encoded two-dimensional coacervate droplet arrays by acoustic wave patterning

The spontaneous assembly of chemically encoded, molecularly crowded, water-rich micro-droplets into periodic defect-free two-dimensional arrays is achieved in aqueous media by a combination of an acoustic standing wave pressure field and in situ complex coacervation. Acoustically mediated coalescence of primary droplets generates single-droplet per node micro-arrays that exhibit variable surface-attachment properties, spontaneously uptake dyes, enzymes and particles, and display spatial and time-dependent fluorescence outputs when exposed to a reactant diffusion gradient. In addition, coacervate droplet arrays exhibiting dynamical behaviour and exchange of matter are prepared by inhibiting coalescence to produce acoustically trapped lattices of droplet clusters that display fast and reversible changes in shape and spatial configuration in direct response to modulations in the acoustic frequencies and fields. Our results offer a novel route to the design and construction of ‘water-in-water' micro-droplet arrays with controllable spatial organization, programmable signalling pathways and higher order collective behaviour

Chitin and carbon nanotube composites as biocompatible scaffolds for neuron growth

Preparation of biocompatible and electrically-conducting chitin nanotube composite scaffold for potential use in implantable electrode for stimulation and repair of neurons.</p

Nonequilibrium Spatiotemporal Sensing within Acoustically Patterned Two-Dimensional Protocell Arrays

Acoustically trapped periodic arrays of horseradish peroxidase (HRP)-loaded poly­(diallydimethylammonium chloride) / adenosine 5′-triphosphate coacervate microdroplet-based protocells exhibit a spatiotemporal biochemical response when exposed to a codiffusing mixture of substrate molecules (<i>o</i>-phenylenediamine (<i>o</i>-PD) and hydrogen peroxide (H₂O₂)) under nonequilibrium conditions. Unidirectional propagation of the chemical concentration gradients gives rise to time- and position-dependent fluorescence signal outputs from individual coacervate microdroplets, indicating that the organized protocell assembly can dynamically sense encoded information in the advancing reaction-diffusion front. The methodology is extended to arrays comprising spatially separated binary populations of HRP- or glucose oxidase-containing coacervate microdroplets to internally generate a H₂O₂ signal that chemically connects the two protocell communities via a concerted biochemical cascade reaction. Our results provide a step toward establishing a systematic approach to study dynamic interactions between organized protocell consortia and propagating reaction-diffusion gradients, and offer a new methodology for exploring the complexity of protocellular communication networks operating under nonequilibrium conditions