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Conventional protein engineering methods for modifying protein nanopores are typically limited to 20 natural amino acids, which restrict the diversity of the nanopores in structure and function. To enrich the chemical environment inside the nanopore, we employed the genetic code expansion (GCE) technique to site‐specifically incorporate the unnatural amino acid (UAA) into the sensing region of aerolysin nanopores. This approach leveraged the efficient pyrrolysine‐based aminoacyl‐tRNA synthetase‐tRNA pair for a high yield of pore‐forming protein. Both molecular dynamics (MD) simulations and single‐molecule sensing experiments demonstrated that the conformation of UAA residues provided a favorable geometric orientation for the interactions of target molecules and the pore. This rationally designed chemical environment enabled the direct discrimination of multiple peptides containing hydrophobic amino acids. Our work provides a new framework for endowing nanopores with unique sensing properties that are difficult to achieve using classical protein engineering approaches. [ABSTRACT FROM AUTHOR]

The electronic coupling between a metal electrode and single nano‐entities is of unfading significance which impacts the heterogeneous electron transfer. Herein, we demonstrated a simple optical technique for directly imaging the transient interfacial electronic coupling events during electrochemical oxidation of single Ag nanoparticles on Au electrode. The electronic coupling brings out a dramatic dip behavior of bright field imaging traces, and is conductive to cross the energy barrier of oxidation for single silver nanoparticles. This dip behavior is further verified by in situ vis‐transmission spectroscopy, and the heterogeneity of the Au−Ag electronic coupling down to single‐nanoparticle level is uncovered by unifying the morphology and size of individual silver nanoparticles. These results suggest the interfacial electronic coupling facilitates electron transfer of single nanoparticles, and provide important insight into understanding detailed mechanism of nanoelectrochemistry. [ABSTRACT FROM AUTHOR]

Electrochemical CO2‐to‐CO conversion provides a possible way to address problems associated with the greenhouse effect; however, developing low‐cost electrocatalysts to mediate high‐efficiency CO2 reduction remains a challenge on account of the limited understanding of the nature of the real active sites. Herein, we reveal the Znδ+ metalloid sites as the real active sites of stable nonstoichiometric ZnOx structure derived from Zn2P2O7 through operando X‐ray absorption fine structure analysis in conjunction with evolutionary‐algorithm‐based global optimization. Furthermore, theoretical and experimental results demonstrated that Znδ+ metalloid active sites could facilitate the activation of CO2 and the hydrogenation of *CO2, thus accelerating the CO2‐to‐CO conversion. Our work establishes a critical fundamental understanding of the origin of the real active center in the zinc‐based electrocatalysts for CO2 reduction reaction. [ABSTRACT FROM AUTHOR]

Medicinal phytochemicals, such as artemisinin and taxol, have impacted the world, and hypericin might do so if its availability issue could be addressed. Hypericin is the hallmark component of Saint John's wort (Hypericum perforatum L.), an approved depression alleviator documented in the US, European, and British pharmacopoeias with its additional effectiveness against diverse cancers and viruses. However, the academia‐to‐industry transition of hypericin remain hampered by its low in planta abundance, unfeasible bulk chemical synthesis, and unclear biosynthetic mechanism. Here, we present a strategy consisting of the hypericin‐structure‐centered modification and reorganization of microbial biosynthetic steps in the repurposed cells that have been tamed to enable the designed consecutive reactions to afford hypericin (43.1 mg L−1), without acquiring its biosynthetic knowledge in native plants. The study provides a synthetic biology route to hypericin and establishes a platform for biosustainable access to medicinal phytochemicals. [ABSTRACT FROM AUTHOR]

We design the tetraalkylammonium carboxylate‐initiated superfast polymerization on α‐amino acid N‐carboxyanhydrides (NCA) for efficient synthesis of polypeptides. Carboxylates, as a new class of initiator for NCA polymerization, can initiate the superfast NCA polymerization without the need of extra catalysts and the polymerization can be operated in open vessels at ambient condition without the use of glove box. Tetraalkylammonium carboxylate‐initiated polymerization on NCA easily affords block copolymers with at least 15 blocks. Moreover, this method avoids tedious purification steps and enables direct polymerization on crude NCAs in aqueous environments to prepare polypeptides and one‐pot synthesis of polypeptide nanoparticles. These advantages and the mild polymerization condition of tetraalkylammonium carboxylate‐initiated NCA polymerization imply its great potential in functional exploration and application of polypeptides. [ABSTRACT FROM AUTHOR]

Kharasch–Sosnovsky reaction is one of the most powerful methods for allylic oxidation of alkenes. However, the inherent radical mechanism and use of peroxides as both oxidants and oxygen nucleophiles render dearth of universal catalytic systems for highly enantioselective variants and limited scope. Herein, an alternative to the asymmetric Kharasch–Sosnovsky reaction that utilized a chiral copper catalyst and purple‐LED irradiation to enable the three‐component coupling of 1,3‐dienes, oxime esters, and carboxylic acids is reported. This protocol features mild conditions, remarkable scope and functional group tolerance as evidenced by >80 examples and utility in the late‐stage modification of pharmaceuticals and natural products. Detailed mechanistic studies provide evidences for the radical‐based reaction pathway. [ABSTRACT FROM AUTHOR]

One‐dimensional (1D) hyperbranched heterostructures (HBHSs) with abundant interfaces are rendered with various interfacial phenomena and functionalities. However, the rational synthesis of 1D HBHSs with desired spatial architecture and specific interface remains a great challenge. Here, we report a seeded growth method for controlled synthesis of two extraordinary types of HBHSs, in which high‐intensity of CdS branches selectively grow on 1D nanowire (NW) trunks with different growth behaviors. The composition of the HBHSs can be further tuned by combining with cation exchange method, which enriches the variety of the HBHSs. The optoelectronic devices based on a single HBHS were fabricated and exhibit a better photoresponse performance compared with that of a single NW trunk. This advance provides a strategy for the controlled synthesis HBHSs with complex morphology and offers a platform for exploring their applications for photo harvesting and conversion. [ABSTRACT FROM AUTHOR]

Although two-dimensional (2D) metal oxide/sulfide hybrid nanostructures have been synthesized, the facile preparation of ultrathin 2D nanosheets in high yield still remains a challenge. Herein, we report the first high-yield preparation of solution-processed ultrathin 2D metal oxide/sulfide hybrid nanosheets, that is, Ti xTa1− xS yO z ( x=0.71, 0.49, and 0.30), from Ti xTa1− xS2 precursors. The nanosheet exhibits strong absorbance in the near-infrared region, giving a large extinction coefficient of 54.1 L g−1 cm−1 at 808 nm, and a high photothermal conversion efficiency of 39.2 %. After modification with lipoic acid-conjugated polyethylene glycol, the nanosheet is a suitable photothermal agent for treatment of cancer cells under 808 nm laser irradiation. This work provides a facile and general method for the preparation of 2D metal oxide/sulfide hybrid nanosheets. [ABSTRACT FROM AUTHOR]

The ability to monitor and quantify glutathione (GSH) in live cells is essential in order to gain a detailed understanding of GSH-related pathological events. However, owing to their irreversible response mechanisms, most existing fluorescent GSH probes are not suitable for this purpose. We have developed a ratiometric fluorescent probe (QG- 1) for quantitatively monitoring cellular GSH. The probe responds specifically and reversibility to GSH with an ideal dissociation constant ( Kd) of 2.59 m m and a fast response time ( t1/2=5.82 s). We also demonstrate that QG- 1 detection of GSH is feasible in a model protein system. QG- 1 was found to have extremely low cytotoxicity and was applied to determine the GSH concentration in live HeLa cells (5.40±0.87 m m). [ABSTRACT FROM AUTHOR]

The incorporation of metal-organic frameworks (MOFs) into membrane-shaped architectures is of great importance for practical applications. The currently synthesized MOF-based membranes show many disadvantages, such as poor compatibility, low dispersity, and instability, which severely limit their utility. Herein, we present a general, facile, and robust approach for the synthesis of MOF-based composite membranes through the in situ growth of MOF plates in the channels of anodized aluminum oxide (AAO) membranes. After being used as catalysis reactors, they exhibit high catalytic performance and stability in the Knoevenagel condensation reaction. The high catalytic performance might be attributed to the intrinsic structure of MOF-based composite membranes, which can remove the products from the reaction zone quickly, and prevent the aggregation and loss of catalysts during reaction and recycling process. [ABSTRACT FROM AUTHOR]

The ability to analyze highly toxic chemical warfare agents (CWAs) and related chemicals in a rapid and precise manner is essential in order to alleviate serious threats to humankind and public security caused by unexpected terrorist attacks and industrial accidents. In this investigation, we designed a o-phenylenediamine-pyronin linked dye that is capable of both fluorogenic and colorimetric discrimination between phosgene and the prototypical nerve-agent mimic, diethyl chlorophosphate (DCP) in the solution or gas phase. Moreover, this dye has been used to construct a portable kit that can be employed for real-time monitoring of DCP and phosgene in the field, both in a discriminatory manner, and in a simple and safe way. [ABSTRACT FROM AUTHOR]

Although many two-dimensional (2D) hybrid nanostructures are being prepared, the engineering of epitaxial 2D semiconductor hetero-nanostructures in the liquid phase still remains a challenge. The preparation of 2D semiconductor hetero-nanostructures by epitaxial growth of metal sulfide nanocrystals, including CuS, ZnS and Ni3S2, is achieved on ultrathin TiS2 nanosheets by a simple electrochemical approach by using the TiS2 crystal and metal foils. Ultrathin CuS nanoplates that are 50-120 nm in size and have a triangular/hexagonal shape are epitaxially grown on TiS2 nanosheets with perfect epitaxial alignment. ZnS and Ni3S2 nanoplates can be also epitaxially grown on TiS2 nanosheets. As a proof-of-concept application, the obtained 2D CuS-TiS2 composite is used as the anode in a lithium ion battery, which exhibits a high capacity and excellent cycling stability. [ABSTRACT FROM AUTHOR]

Exploration of low-cost and earth-abundant photocatalysts for highly efficient solar photocatalytic water splitting is of great importance. Although transition-metal dichalcogenides (TMDs) showed outstanding performance as co-catalysts for the hydrogen evolution reaction (HER), designing TMD-hybridized photocatalysts with abundant active sites for the HER still remains challenge. Here, a facile one-pot wet-chemical method is developed to prepare MS2-CdS ( M=W or Mo) nanohybrids. Surprisedly, in the obtained nanohybrids, single-layer MS2 nanosheets with lateral size of 4-10 nm selectively grow on the Cd-rich (0001) surface of wurtzite CdS nanocrystals. These MS2-CdS nanohybrids possess a large number of edge sites in the MS2 layers, which are active sites for the HER. The photocatalytic performances of WS2-CdS and MoS2-CdS nanohybrids towards the HER under visible light irradiation (>420 nm) are about 16 and 12 times that of pure CdS, respectively. Importantly, the MS2-CdS nanohybrids showed enhanced stability after a long-time test (16 h), and 70 % of catalytic activity still remained. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) copper-based ternary and quaternary semiconductors are promising building blocks for the construction of efficient solution-processed photovoltaic devices at low cost. However, the facile synthesis of such 2D nanoplates with well-defined shape and uniform size remains a challenge. Reported herein is a universal template-mediated method for preparing copper-based ternary and quaternary chalcogenide nanoplates, that is, CuInS2, CuIn xGa1− xS2, and Cu2ZnSnS4, by using a pre-synthesized CuS nanoplate as the starting template. The various synthesized nanoplates are monophasic with uniform thickness and lateral size. As a proof of concept, the Cu2ZnSnS4 nanoplates were immobilized on a Mo/glass substrate and used as semiconductor photoelectrode, thus showing stable photoelectrochemical response. The method is general and provides future opportunities for fabrication of cost-effective photovoltaic devices based on 2D semiconductors. [ABSTRACT FROM AUTHOR]

Semiconducting nanosheets with microscale lateral size are attractive building blocks for the fabrication of electronic and optoelectronic devices. The phase-controlled chemical synthesis of semiconducting nanosheets is of particular interest, because their intriguing properties are not only related to their size and shape, but also phase-dependent. Herein, a facile method for the synthesis of phase-pure, microsized, two-dimensional (2D) CuSe nanosheets with an average thickness of approximately 5 nm is demonstrated. These hexagonal-phased CuSe nanosheets were transformed into cubic-phased Cu2− xSe nanosheets with the same morphology simply by treatment with heat in the presence of CuI cations. The phase transformation, proposed to be a template-assisted process, can be extended to other systems, such as CuS and Cu1.97S nanoplates. Our study offers a new method for the phase-controlled preparation of 2D nanomaterials, which are not readily accessible by conventional wet-chemical methods. [ABSTRACT FROM AUTHOR]