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Vanadium‐based materials are fascinating potential cathodes for high energy density Zn‐ion batteries (ZIBs), due to their high capacity arising from multi‐electron redox chemistry. Most vanadium‐based materials suffer from poor rate capability, however, owing to their low conductivity and large dimension. Here, we propose the application of V2C MXene (V2CTx), a conductive 2D nanomaterial, for achieving high energy density ZIBs with superior rate capability. Through an initial charging activation, the valence of surface vanadium in V2CTx cathode is raised significantly from V2+/V3+ to V4+/V5+, forming a nanoscale vanadium oxide (VOx) coating that effectively undergoes multi‐electron reactions, whereas the inner V‐C‐V 2D multi‐layers of V2CTx are intentionally preserved, providing abundant nanochannels with intrinsic high conductivity. Owing to the synergistic effects between the outer high‐valence VOx and inner conductive V‐C‐V, the activated V2CTx presents an ultrahigh rate performance, reaching 358 mAh g−1 at 30 A g−1, together with remarkable energy and power density (318 Wh kg−1/22.5 kW kg−1). The structural advantages of activated V2CTx are maintained after 2000 cycles, offering excellent stability with nearly 100% Coulombic efficiency. This work provides key insights into the design of high‐performance cathode materials for advanced ZIBs. [ABSTRACT FROM AUTHOR]

We demonstrate the use of two different wavelength ranges of excitation light as inputs to remotely trigger the responses of the self-assembled DNA devices (D-OR). As an important feature of this device, the dependence of the readout fluorescent signals on the two external inputs, UV excitation for 1 min and/or near infrared irradiation (NIR) at 800 nmfs laser pulses, can mimic function of signal communication in OR logic gates. Their operations could be reset easily to its initial state. Furthermore, these DNA devices exhibit efficient cellular uptake, low cytotoxicity, and high bio-stability in different cell lines. They are considered as the first example of a photo-responsive DNA logic gate system, as well as a biocompatible, multi-wavelength excited system in response to UV and NIR. This is an important step to explore the concept of photo-responsive DNA-based systems as versatile tools in DNA computing, display devices, optical communication, and biology. [ABSTRACT FROM AUTHOR]

The charge properties of polyamide membranes play a crucial role in the selective ionic and molecular sieving processes. These polyamide membranes fabricated through interfacial polymerization normally exhibit a front surface enriched with carboxyl groups and a rear surface enriched with amine groups, rendering it with a Janus surface charge. However, this disparity in charge properties between the two surfaces has not been thoroughly investigated, despite its importance in understanding the membrane formation mechanism. In this study, polyethylenimine (PEI, M w = 70000 Da) and piperazine (PIP, M w = 86 Da), with distinct molecular size, were employed as aqueous monomers to react with trimesoyl chloride (TMC) at a support-free water hexane interface to synthesize polyamide nanofiltration membranes. The charge differences in the rear and front surface of PEI/TMC and PIP/TMC nanofiltration membrane was fully explored. The PEI/TMC membrane demonstrated a great charge disparity between the two surfaces with a negatively charged (isoelectric point = 5.62) front surface and a positively charged (isoelectric point = 9.59) rear surface. As a result, the rear surface exhibits a higher MgCl 2 rejection (95.6 %) than the front surface (88.9 %). In contrast, the PIP/TMC membrane exhibited a similar negative charge and salt rejections on both surfaces. Moreover, the rear surface of PEI/TMC membrane exhibited a great anti-fouling performance to positively charged lysozyme (FDR = 51.1 %, FRR = 88.8 %). This work provides valuable insights into the mechanisms of an interfacial polymerization process [Display omitted] • Polyamide nanofiltration membranes, synthesized from a larger aqueous monomer PEI, demonstrate enhanced Janus surface charge properties. • The rear surface of PEI/TMC membranes exhibit a higher MgCl 2 rejection (95.6 %) than the front surface (88.9 %). • The rear surface of PEI/TMC membranes demonstrate higher fouling resistance to positively charged foulants but is easily fouled by positively charged foulants. Polyamide nanofiltration membranes, synthesized from a larger aqueous monomer, demonstrate enhanced Janus surface charge properties characterized by a highly positive real surface and a negatively charged frontal surface. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) is a promising cathode material for Zn-ion batteries (ZIBs) due to its intrinsic conductivity and redox activity; however, the achievements of PANI in high-performance ZIBs are largely hindered by its instability during the repeated charge/discharge. Taking advantage of the high conductivity, flexibility, and grafting ability together, a surface-engineered Ti 3 C 2 T x MXene is designed as a silver bullet to fight against the deprotonation and swelling/shrinking issues occurring in the redox process of PANI, which are the origins of its instability. Specifically, the sulfonic-group-grafted Ti 3 C 2 T x (S-Ti 3 C 2 T x ) continuously provides protons to improve the protonation degree of PANI and maintains the polymer backbone at a locally low pH, which effectively inhibits deprotonation and brings high redox activity along with good reversibility. Meanwhile, the conductive and flexible natures of S-Ti 3 C 2 T x assist the fast redox reaction of PANI and concurrently buffer its corresponding swelling/shrinking. Therefore, the S-Ti 3 C 2 T x -enhanced PANI cathode simultaneously achieves a high discharge capacity of 262 mAh g -1 at 0.5 A g -1 , a superior rate capability of 160 mAh g -1 at 15 A g -1 , and a good cyclability over 5000 cycles with 100% coulombic efficiency. This work enlightens the development of versatile MXene via surface engineering for advanced batteries.

A DNA tetrahedron as the most classical and simplest three-dimensional DNA nanostructure has been widely utilized in biomedicine and biosensing. However, the existing assembly approaches usually require harsh thermal annealing conditions, involve the formation of unwanted by-products, and have poor size control. Herein, a facile strategy to fabricate a discrete DNA tetrahedron as a single, thermodynamically stable product in a quantitative yield at room temperature is reported. This system does not require a DNA trigger or thermal annealing treatment to initiate self-assembly. This DNA tetrahedron was made of three chemically ligated triangular-shaped DNAs in unconventional ladder-like arrangements, with measured heights of ∼4.16 ± 0.04 nm, showing extra protections for enzymatic degradation in biological environment. They show substantial cellular uptake in different cell lines via temperature, energy-dependent and clathrin-mediated endocytosis pathways. These characteristics allow our DNA tetrahedron to be used as vehicles for the delivery of very small and temperature-sensitive cargos. This novel assembly strategy developed for DNA tetrahedra could potentially be extended to other highly complex polyhedra; this indicated its generalizability., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)