Plasmonic noble metal nanoparticles have emerged as a promising material in sensitizing wide-bandgap semiconductors for visible-light photocatalysis. Conventional methods in constructing such heterocatalysts suffer from either poor control over the size of the metal nanoparticles or inefficient charge transfer through the metal/semiconductor interface, which limit their photocatalytic activity. To solve this problem, in this work we construct Au/TiO2 photocatalysts by depositing presynthesized colloidal Au nanoparticles with well-controlled sizes to TiO2 nanocrystals and then removing capping ligands on the Au surface through a delicately designed ligand-exchange method, which leads to close Au/TiO2 Schottky contact after a mild annealing process. Benefiting from this unique synthesis strategy, the obtained photocatalysts show superior activity to conventionally prepared photocatalysts in dye decomposition and water-reduction hydrogen production under visible-light illumination. This study not only opens up new opportunities in designing photoactive materials with high stability and enhanced performance for solar energy conversion but also provides a potential solution for the well-recognized challenge in cleaning capping ligands from the surface of colloidal catalyst nanoparticles.

Ultrasmall gold nanoparticles (us-AuNPs, <3 nm) have been recently recognized as surprisingly active and extraordinarily effective green catalysts. Their stability against sintering during reactions, however, remains a serious issue for practical applications. Encapsulating such small nanoparticles in a layer of porous silica can dramatically enhance the stability, but it has been extremely difficult to achieve using conventional sol-gel coating methods due to the weak metal/oxide affinity. In this work, we address this challenge by developing an effective protocol for the synthesis of us-AuNP@SiO2 single-core/shell nanospheres. More specifically, we take an alternative route by starting with ultrasmall gold hydroxide nanoparticles, which have excellent affinity to silica, then carrying out controllable silica coating in reverse micelles, and finally converting gold hydroxide particles into well-protected us-AuNPs. With a single-core/shell configuration that prevents sintering of nearby us-AuNPs and amino group modification of the Au/SiO2 interface that provides additional coordinating interactions, the resulting us-AuNP@SiO2 nanospheres are highly stable at high temperatures and show high activity in catalytic CO oxidation reactions. A dramatic and continuous increase in the catalytic activity has been observed when the size of the us-AuNPs decreases from 2.3 to 1.5 nm, which reflects the intrinsic size effect of the Au nanoparticles on an inert support. The synthesis scheme described in this work is believed to be extendable to many other ultrasmall metal@oxide nanostructures for much broader catalytic applications.

Isolation of specific rare cell subtypes from whole blood is critical in cellular analysis and important in basic and clinical research. Traditional immunomagnetic cell capture suffers from suboptimal sensitivity, specificity, and time- and cost-effectiveness. Mimicking the features of octopuses, a device termed a “NanoOctopus” was developed for cancer cell isolation in whole blood. The device consists of long multimerized aptamer DNA strands, or tentacle DNA, immobilized on magnetic microparticle surfaces. Their ultrahigh sensitivity and specificity are attributed to multivalent binding of the tentacle DNA to cell receptors without steric hindrance. The simple, quick, and noninvasive capture and release of the target cells allows for extensive downstream cellular and molecular analysis, and the time- and cost-effectiveness of fabrication and regeneration of the devices makes them attractive for industrial manufacture.

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Using a mixture of NaNO3 and NaF as molten salt and MnSO4 and AgNO3 as metal precursors, 0.13 wt % Ag/Mn2O3 nanowires (0.13Ag/Mn2O3-ms) were fabricated after calcination at 420 °C for 2 h. Compared to the counterparts derived via the impregnation and poly(vinyl alcohol)-protected reduction routes as well as the bulk Mn2O3-supported silver catalyst, 0.13Ag/Mn2O3-ms exhibited a much higher catalytic activity for toluene oxidation. At a toluene/oxygen molar ratio of 1/400 and a space velocity of 40,000 mL/(g h), toluene could be completely oxidized into CO2 and H2O at 220 °C over the 0.13Ag/Mn2O3-ms catalyst. Furthermore, the toluene consumption rate per gram of noble metal over 0.13Ag/Mn2O3-ms was dozens of times as high as that over the supported Au or AuPd alloy catalysts reported in our previous works. It is concluded that the excellent catalytic activity of 0.13Ag/Mn2O3-ms was associated with its high dispersion of silver nanoparticles on the surface of Mn2O3 nanowires and good low-temperature reducibility. Due to high efficiency, good stability, low cost, and convenient preparation, 0.13Ag/Mn2O3-ms is a promising catalyst for the practical removal of volatile organic compounds.

Andrographolide, the main active component extracted from Andrographis paniculata (Burm.f.) Wall. ex Nees, exerts anti-inflammatory effects; however, the principal molecular mechanisms remain unclear. The objective of this study was to investigate the molecular mechanisms of Andrographolide in modifying lipopolysaccharide- (LPS-) induced signaling pathway in RAW264.7 cells. An in vitro model of inflammation was induced by LPS in mouse RAW264.7 cells in the presence of Andrographolide. The concentration and expression levels of proinflammatory cytokines were determined by an enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. The nuclear level of NF-κB was measured by an electrophoretic mobility shift assay (EMSA). The expression levels of NF-κB, p38, ERK, and JNK were determined by western blot. Andrographolide dose-dependently inhibited the release and mRNA expression of TNF-α, IL-6, and IL-1β in LPS-stimulated RAW264.7 cells. The nuclear level of p65 protein was decreased in Andrographolide treatment group. Western blot analysis showed that Andrographolide suppressed LPS-induced NF-κB activation and the phosphorylation of IkBa, ERK1/2, JNK, and p38. These results suggest that Andrographolide exerts an anti-inflammatory effect by inhibiting the activation of NF-κB/MAPK signaling pathway and the induction of proinflammatory cytokines.

Size- and shape-focusing of palladium nanocrystals have been successfully achieved through the Ostwald ripening process induced by a redox reaction.

The sodium (Na)‐metal anode with high theoretical capacity and low cost is promising for construction of high‐energy‐density metal batteries. However, the unsatisfactory interface between Na and the liquid electrolyte induces tardy ion transfer kinetics and dendritic Na growth, especially at ultralow temperature (−40 °C). Herein, an artificial heterogeneous interphase consisting of disodium selenide (Na2Se) and metal vanadium (V) is produced on the surface of Na (Na@Na2Se/V) via an in situ spontaneous chemical reaction. Such interphase layer possesses high sodiophilicity, excellent ionic conductivity, and high Young's modulus, which can promote Na‐ion adsorption and transport, realizing homogenous Na deposition without dendrites. The symmetric Na@Na2Se/V cell exhibits outstanding cycling life span of over 1790 h (0.5 mA cm−2/1 mAh cm−2) in carbonate‐based electrolyte. More remarkably, ab initio molecular dynamics simulations reveal that the artificial Na2Se/V hybrid interphase can accelerate the desolvation of solvated Na+ at −40 °C. The Na@Na2Se/V electrode thus exhibits exceptional electrochemical performance in symmetric cell (over 1500 h at 0.5 mA cm−2/0.5 mAh cm−2) and full cell (over 700 cycles at 0.5 C) at −40 °C. This work provides an avenue to design artificial heterogeneous interphase layers for superior high‐energy‐density metal batteries at ambient and ultralow temperatures.