Efficientand rapid detection of physiologically important species has drawn much attention in medical theranostics. [1] For example, precise determination of the physiological levels of dopamine (DA), an important neurotransmitter for the function of the central nervous systems, is of great clinical importance in the diagnoses, prevention, and treatment of neurological disorders such as Schizophrenia, Huntington's disease, and Parkinson's disease. [1,2] To date, a large number of analytical strategies, based on electrochemical techniques, spectrophotometric methods, and chromatography, have been developed for DA determination. [3] Despite the increasing sensitivity of these methods, the complexity of biofluids still presents a great challenge to these methods to provide technically simple, timely, and in particular point of care DA detection directly in the biofluid samples.Compared to traditional detection methods, paper-based analytical test strips can provide fast and convenient procedures for on-site and visual analysis without using costly instruments or devices. [4] Moreover, a test strip commonly requires only tiny amount of sample (5-20 µL), [5] which is an important merit for continuous DA detection during long-term disease monitoring. In this context, we present here a facile test strip, based on dual-emission fluorescent [6] molecularly imprinted polymers (DE-MIPs), [7] for colorimetric visualization of DA direct in a typical biofluid, i.e., serum samples (Scheme 1). The DE-MIPs were designed with specific DA affinity and ratiometric fluorescence property [8] by combining two types of quantum dots (QDs) with different color emission (i.e., red and blue) through a molecular imprinting process. [9] Specifically, the blue QDs were embedded in silica nanocores to maintain constant fluorescence intensity; while the red QDs were mixed into the imprinted polymer shell, thus enabling to interact with DA molecules to induce fluorescence quenching during DA recognition (Scheme 1a). In this way, DA binding could be colorimetrically visualized by the DE-MIPs, owing to the DA-induced quenching of the red-light emission and subsequently changes of the hybrid fluorescence color (red and blue). To simplify DA detection procedure and reduce sample consumption, the DE-MIPs were then coated on a filter paper to obtain a DA test strip Paper-based assays for detection of physiologically important species are needed in medical theranostics owning to their superiorities in point of care testing, daily monitoring, and even visual readout by using chromogenic materials. In this work, a facile test strip is developed for visual detection of a neurotransmitter dopamine (DA) based on dual-emission fluorescent molecularly imprinted polymer nanoparticles (DE-MIPs). The DE-MIPs, featured with tailor-made DA affinity and good anti-interference, exhibit DA concentration-dependent fluorescent colors, due to the variable ratios of dual-emission fluorescence caused by DA binding and quenching. By facile coating DE-MIPs on a filter ...

Crystal phase control still remains a challenge for the precise synthesis of 2D layered metal dichalcogenide (LMD) materials. The T′ phase structure has profound influences on enhancing electrical conductivity, increasing active sites, and improving intrinsic catalytic activity, which are urgently needed for enhancing hydrogen evolution reaction (HER) activity. Theoretical calculations suggest that metastable T′ phase 2D Sn 1−x W x S 2 alloys can be formed by combining W with 1T tin disulfide (SnS 2 ) as a template to achieve a semiconductor-to-metallic transition. Herein, 2D Sn 1−x W x S 2 alloys with varying x are prepared by adjusting the molar ratio of reactants via hydrothermal synthesis, among which Sn 0.3 W 0.7 S 2 displays a maximum of concentration of 81% in the metallic phase and features a distorted octahedral-coordinated metastable 1T′ phase structure. The obtained 1T′-Sn 0.3 W 0.7 S 2 has high intrinsic electrical conductivity, lattice distortion, and defects, showing a prominently improved HER catalytic performance. Metallic Sn 0.3 W 0.7 S 2 coupled with carbon black exhibits at least a 215-fold improvement compared to pristine SnS 2 . It has excellent long-term durability and HER activity. This work reveals a general phase transition strategy by using T phase materials as templates and merging heteroatoms to achieve synthetic metastable phase 2D LMDs that have a significantly improved HER catalytic performance.

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The catalytic performance of Molybdenum disulfide (MoS2) has been still far from that of Pt‐based catalysts for inadequate active sites and sluggish electron transfer kinetics. Through engineering the interface between MoS2‐based materials and supported substrates, hybrid Ru‐doped MoS2 on carbonized lignin (CL) is designed and prepared as efficient catalyst for hydrogen evolution reaction (HER). The CL substrate not only facilitates the growth of MoS2 nanoflowers, but also promotes the electron transfer. Ru doping increases active sites greatly for HER. The hybrid catalyst achieves a low onset overpotential of 25 mV and a low Tafel slope of 46 mV dec−1. The favorable HER activity ascribes to the interfacial interaction between MoS2 and CL. Density functional theory calculations further confirm the improved HER performance with doped Ru atoms. This study presents a prototype application to design electrocatalysts with enhanced carrier mobility and high‐density active sites based on interface effect.

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