A single-layer MoS2 nanosheet exhibits high fluorescence quenching ability and different affinity toward ssDNA versus dsDNA. As a proof of concept, the MoS2 nanosheet has been successfully used as a sensing platform for the detection of DNA and small molecules.

In this work, we report the design of a novel graphene-based molecular beacon (MB) that could sensitively and selectively detect specific DNA sequences. The ability of water-soluble graphene oxide (GO) to differentiated hairpin and dsDNA offered a new approach to detect DNA. We found that the background fluorescence of MB was significantly suppressed in the presence of GO, which increased the signal-to-background ratio, hence the sensitivity. Moreover, the single-mismatch differentiation ability of hairpin DNA was maintained, leading to high selectivity of this new method.

Based on gold nanoparticles (AuNPs) and engineered DNA aptamers, we designed a novel bioassay strategy for the detection of adenosine as a small target molecule. In this design, an aptamer is engineered to consist of two pieces of random-coil like ssDNA which are respectively attached to AuNPs through their 5'-thiol-modified end. They can reassemble into the intact aptamer tertiary structure and induce nanoparticle aggregation in the presence of the specific target. Results have demonstrated that gold nanoparticles can effectively differentiate these two different DNA structures via their characteristic surface plasmon resonance-based color change. With this method, adenosine can be selectively detected in the low micromolar range, which means that the strategy reported here can be applicable to the detection of several other small target molecules.

A variety of nanomaterials have shown extraordinarily high quenching ability toward a broad range of fl uorophores. Recently, there has been intense interest in developing new tools for fl uorescent DNA analysis in solution or inside the cell based on this property, and by exploiting interactions between these nanoscale "superquenchers" and DNA molecules in the singlestranded (ss-) or double-stranded (ds-) forms. Here, a comparative study on the nanoqueching effects is performed by using a series of nanomaterials with different dimensions, i.e., gold nanoparticles (AuNPs, 0D), carbon nanotubes (CNTs, 1D), and graphene oxide (GO, 2D). The quenching effi ciency, kinetics, differentiation ability, and infl uencing factors such as concentration and ionic strength are studied. Interestingly, GO exhibits superior quenching abilities to the other two materials in both the quenching effi ciency and kinetics. As a result, a GO-based fl uorescent sensor, designed in a simple mix-and-detect format, can detect concentrations of DNA as low as 0.2 n M , which is better than either CNTs or AuNPs by an order of magnitude. This sensor can also differentiate single-base mismatches much better than either CNTs-or AuNPs-based sensors. This study paves the way to better choice of nanomaterials for bioanalysis and elaborate design of biosensors for both in vitro diagnosis and in vivo bioimaging.

Lithium-sulfur batteries, notable for high theoretical energy density, environmental benignity, and low cost, hold great potential for next-generation energy storage. Polysulfides, the intermediates generated during cycling, may shuttle between electrodes, compromising the energy density and cycling life. We report herein a class of regenerative polysulfide-scavenging layers (RSL), which effectively immobilize and regenerate polysulfides, especially for electrodes with high sulfur loadings (e.g., 6 mg cm). The resulting cells exhibit high gravimetric energy density of 365 Wh kg, initial areal capacity of 7.94 mAh cm, low self-discharge rate of 2.45% after resting for 3 days, and dramatically prolonged cycling life. Such blocking effects have been thoroughly investigated and correlated with the work functions of the oxides as well as their bond energies with polysulfides. This work offers not only a class of RSL to mitigate shuttling effect but also a quantified design framework for advanced lithium-sulfur batteries.

Elucidating the intrinsic relationship between diseases and lipid droplet (LD) polarity remains a great challenge owing to the lack of the research on multiple disease models. Until now, the visualization of abnormal LD polarity in models of inflammation and clinical cancer patient samples has not been achieved. To meet the urgent challenge, we facilely synthesized a robust LD-specific and polarity-sensitive fluorescent probe (LD-TTP), which consists of a triphenylamine segment as an electron-donor group (D) and a pyridinium as an electron-acceptor moiety (A), forming a typical D−π−A molecular configuration. Owing to the unique intramolecular charge transfer effect, LD-TTP exhibits high sensitivity to polarity change in the linear range from Δf = 0.258 to 0.312, with over 278-fold fluorescence enhancement. Moreover, we revealed that LD-TTP possessed satisfactory ability for sensitively monitoring LDpolarity changes in living cells. Using LD-TTP, we first demonstrated the detection of LD-polarity changes in fatty liver tissues and inflammatory living mice via confocal laser scanning fluorescence imaging. Surprisingly, the visualization of LD polarity has been achieved not only at the cellular levels and living organs but also in surgical specimens from cancer patients, thus holding great potential in the clinical diagnosis of human cancer. All these features render LD-TTP an effective tool for medical diagnosis of LD polarity-related diseases.

We designed a single-fluorophore-tagged hairpin-structured nano-beacon probe by using a superquencher, graphene oxide (GO), based on which a new method for the analysis of DNA phosphorylation detection was developed.

As an excellent electrocatalyst, platinum (Pt) is often deposited as a thin layer on a nanoscale substrate to achieve high utilization efficiency. However, the practical application of the as-designed catalysts has been substantially restricted by the poor durability arising from the leaching of cores. Herein, by employing amorphous palladium phosphide (a-Pd-P) as substrates, we develop a class of leaching-free, ultrastable core–shell Pt catalysts with well-controlled shell thicknesses and surface structures for fuel cell electrocatalysis. When a submonolayer of Pt is deposited on the 6 nm nanocubes, the resulting Pd@a-Pd-P@PtSML core–shell catalyst can deliver a mass activity as high as 4.08 A/mgPt and 1.37 A/mgPd+Pt toward the oxygen reduction reaction at 0.9 V vs the reversible hydrogen electrode and undergoes 50 000 potential cycles with only ∼9% activity loss and negligible structural deformation. As elucidated by the DFT calculations, the superior durability of the catalysts originates from the high corrosion resistance of the disordered a-Pd-P substrates and the strong interfacial Pt–P interactions between the Pt shell and amorphous Pd–P layer.