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Point-of-care testing (POCT) with the advantages of speed, simplicity, portability, and low cost is critical for the measurement of analytes in a variety of environments where access to laboratory infrastructure is lacking. While qualitative POCTs are widely available, quantitative POCTs present significant challenges. Here we describe a novel method that integrates an Au core/Pt shell nanoparticle (Au@PtNP) encapsulated target-responsive hydrogel with a volumetric bar-chart chip (V-Chip) for quantitative POCT. Upon target introduction, the hydrogel immediately dissolves and releases Au@PtNPs, which can efficiently catalyze the decomposition of H2O2 to generate a large volume of O2 to move of an ink bar in the V-Chip. The concentration of the target introduced can be visually quantified by reading the traveling distance of the ink bar. This method has the potential to be used for portable and quantitative detection of a wide range of targets without any external instrument. [ABSTRACT FROM AUTHOR]

Poly(methyl methacrylate) (PMMA) is gaining in popularity in microfluidic devices because of its low cost, excellent optical transparency, attractive mechanical/chemical properties, and simple fabrication procedures. It has been used to fabricate micromixers, PCR reactors, CE and many other microdevices. Here we present the design, fabrication, characterization and application of pneumatic microvalves and micropumps based on PMMA. Valves and pumps are fabricated by sandwiching a PDMS membrane between PMMA fluidic channel and manifold wafers. Valve closing or opening can be controlled by adjusting the pressure in a displacement chamber on the pneumatic layer viaa computer regulated solenoid. The valve provides up to 15.4 µL s−1at 60 kPa fluid pressure and seals reliably against forward fluid pressure as high as 60 kPa. A PMMA diaphragm pump can be assembled by simply connecting three valves in series. By varying valve volume or opening time, pumping rates ranging from nL to µL per second can be accurately achieved. The PMMA based valves and pumps were further tested in a disposable automatic nucleic acid extraction microchip to extract DNA from human whole blood. The DNA extraction efficiency was about 25% and the 260 nm/280 nm UV absorption ratio for extracted DNA was 1.72. Because of its advantages of inexpensive, facile fabrication, robust and easy integration, the PMMA valve and pump will find their wide application for fluidic manipulation in portable and disposable microfluidic devices. [ABSTRACT FROM AUTHOR]

The conventional synthetic methodology for atomically precise gold nanoclusters by using reduction in solution offers only the thermodynamically most stable nanoclusters. Herein, a solubility‐driven isolation strategy is reported to access a metastable gold cluster. The cluster, with the composition of [Au9(PPh3)8]+ (1), displays an unusual, nearly perfect body‐centered cubic (bcc) structure. As revealed by ESI‐MS and UV/Vis measurements, the cluster is metastable in solution and converts to the well‐known [Au11(PPh3)8Cl2]+ (2) within just 90 min. DFT calculations revealed that although both 1 and 2 are eight‐electron superatoms, there is a driving force to convert 1 to 2 as shown by the increased cohesion and larger HOMO–LUMO energy gap of 2. The isolation and crystallization of the metastable gold cluster were achieved in a biphasic reaction system in which reduction of gold precursors and crystallization of 1 took place concurrently. This synthetic protocol represents a successful strategy for investigations of other metastable species in metal nanocluster chemistry. [ABSTRACT FROM AUTHOR]

An effective strategy is developed to synthesize high‐nuclearity Cu clusters, [Cu53(RCOO)10(C≡CtBu)20Cl2H18]+ (Cu53), which is the largest CuI/Cu0 cluster reported to date. Cu powder and Ph2SiH2 are employed as the reducing agents in the synthesis. As revealed by single‐crystal diffraction, Cu53 is arranged as a four‐concentric‐shell Cu3@Cu10Cl2@Cu20@Cu20 structure, possessing an atomic arrangement of concentric M12 icosahedral and M20 dodecahedral shells which popularly occurs in Au/Ag nanoclusters. Surprisingly, Cu53 can be dissolved in diethyl ether and spin coated to form uniform nanoclusters film on organolead halide perovskite. The cluster film can subsequently be converted into high‐quality CuI film via in situ iodination at room temperature. The as‐fabricated CuI film is an excellent hole‐transport layer for fabricating highly stable CuI‐based perovskite solar cells (PSCs) with 14.3 % of efficiency. An effective strategy is developed to synthesize high‐nuclearity Cu53 clusters that are surface‐capped by alkynyl and acetate ligands. These nanoclusters are unexpectedly soluble in ether, enabling the easy formation of high‐quality films. The cluster films are readily converted into high‐quality CuI thin films for applications as a hole transport layer in perovskite solar cells. [ABSTRACT FROM AUTHOR]

Abstract: A general method, using mixed ligands (here diphosphines and thiolates) is devised to turn an achiral metal cluster, Au13Cu2, into an enantiomeric pair by breaking (lowering) the overall molecular symmetry with the ligands. Using an achiral diphosphine, a racemic [Au13Cu2(DPPP)3(SPy)6]+ was prepared which crystallizes in centrosymmetric space groups. Using chiral diphosphines, enantioselective synthesis of an optically pure, enantiomeric pair of [Au13Cu2((2r,4r)/(2s,4s)‐BDPP)3(SPy)6]+ was achieved in one pot. Their circular dichroism (CD) spectra give perfect mirror images in the range of 250–500 nm with maximum anisotropy factors of 1.2×10−3. DFT calculations provided good correlations with the observed CD spectra of the enantiomers and, more importantly, revealed the origin of the chirality. Racemization studies show high stability (no racemization at 70 °C) of these chiral nanoclusters, which hold great promise in applications such as asymmetry catalysis. [ABSTRACT FROM AUTHOR]

By using ethylene glycol and monocarboxylic acid as surface ligands, a series of cyclic Ti-oxo clusters (CTOC) with permanent microporosity are successfully synthesized. With a cyclic {Ti32O16} backbone made of eight connected Ti4 tetrahedral cages that are arranged in a zigzag fashion, the clusters have a 'donut' shape with an inner diameter of 8.3 Å, outer diameter of 26.9 Å and height of 10.4 Å. While both inner and outer walls of the 'donut' clusters are modified by double-deprotonated ethylene glycolates, their upper and lower surfaces are bound by carboxylates and mono-deprotonated ethylene glycolates. The clusters are readily packed into one-dimensional tubes which are further arranged in two different modes into crystalline microporous solids with surface areas over 660 m2 g−1, depending on the surface carboxylates. The solid with olefin-bearing carboxylates exhibits a superior CO2 adsorption capacity of 40 cm3 g−1 at 273 K under 1 atm. Moreover, the mono-deprotonated ethylene glycolates on the clusters are demonstrated to be highly exchangeable by other alcohols, providing a nice platform for creating microporous solids or films with a wide variety of surface functionalities. [ABSTRACT FROM AUTHOR]

The synthesis, structure, substitution chemistry, and optical properties of the gold-centered cubic monocationic cluster [Au@Ag8@Au6(C≡CtBu)12]+ are reported. The metal framework of this cluster can be described as a fragment of a body-centered cubic (bcc) lattice with the silver and gold atoms occupying the vertices and the body center of the cube, respectively. The incorporation of alkali metal atoms gave rise to [MnAg8− nAu7(C≡CtBu)12]+ clusters ( n=1 for M=Na, K, Rb, Cs and n=2 for M=K, Rb), with the alkali metal ion(s) presumably occupying the vertex site(s), whereas the incorporation of copper atoms produced [CunAg8Au7− n(C≡CtBu)12]+ clusters ( n=1-6), with the Cu atom(s) presumably occupying the capping site(s). The parent cluster exhibited strong emission in the near-IR region ( λmax=818 nm) with a quantum yield of 2 % upon excitation at λ=482 nm. Its photoluminescence was quenched upon substitution with a Na+ ion. DFT calculations confirmed the superatom characteristics of the title compound and the sodium-substituted derivatives. [ABSTRACT FROM AUTHOR]

The synthesis, structure, substitution chemistry, and optical properties of the gold-centered cubic monocationic cluster [Au@Ag8@Au6(C≡CtBu)12]+ are reported. The metal framework of this cluster can be described as a fragment of a body-centered cubic (bcc) lattice with the silver and gold atoms occupying the vertices and the body center of the cube, respectively. The incorporation of alkali metal atoms gave rise to [MnAg8− nAu7(C≡CtBu)12]+ clusters ( n=1 for M=Na, K, Rb, Cs and n=2 for M=K, Rb), with the alkali metal ion(s) presumably occupying the vertex site(s), whereas the incorporation of copper atoms produced [CunAg8Au7− n(C≡CtBu)12]+ clusters ( n=1-6), with the Cu atom(s) presumably occupying the capping site(s). The parent cluster exhibited strong emission in the near-IR region ( λmax=818 nm) with a quantum yield of 2 % upon excitation at λ=482 nm. Its photoluminescence was quenched upon substitution with a Na+ ion. DFT calculations confirmed the superatom characteristics of the title compound and the sodium-substituted derivatives. [ABSTRACT FROM AUTHOR]

Biomedizinische Analyse Der Gasdruck lässt sich als Auslesesignal für ein hoch empfindliches bioanalytisches Instrument verwenden, wie C. Yang et al. in ihrer Zuschrift auf S. 10594 ff. demonstrieren. Die Kombination von H2O2 ‐ Zersetzung mit einem Antikörper ‐ Assay ermöglicht die Detektion verschiedener Analyten. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate that a very familiar, yet underutilized, physical parameter-gas pressure-can serve as signal readout for highly sensitive bioanalysis. Integration of a catalyzed gas-generation reaction with a molecular recognition component leads to significant pressure changes, which can be measured with high sensitivity using a low-cost and portable pressure meter. This new signaling strategy opens up a new way for simple, portable, yet highly sensitive biomedical analysis in a variety of settings. [ABSTRACT FROM AUTHOR]

Au nanoparticles epitaxially grown on Fe3O4 in Au (6.7 nm)-Fe3O4 dumbbell nanoparticles exhibit excellent stability against sintering, but display negligible catalytic activity in CO oxidation. Starting from various supported Au (6.7 nm)-Fe3O4 catalysts prepared by the colloidal deposition method, we have unambiguously identified the significance of the Au-TiO2 interface in CO oxidation, without any possible size effect of Au. In situ thermal decomposition of TiO2 precursors on Au-Fe3O4 was found to be an effective way to increase the Au-TiO2 interface and thereby optimize the catalytic performance of TiO2-supported Au-Fe3O4 dumbbell nanoparticles. By reducing the size of Fe3O4 from 15.2 to 4.9 nm, the Au-TiO2 contact was further increased so that the resulting TiO2-supported Au (6.7 nm)-Fe3O4 (4.9 nm) dumbbell particles become highly efficient catalysts for CO oxidation at room temperature. [ABSTRACT FROM AUTHOR]