Polymer Carbon Nanodots: A Novel Electrochemiluminophore for Dual Mode Detection of Ferric Ions.

The development of simple and effective dual-mode analytical methods plays crucial regulatory roles in the discrimination of relevant target species, because of their built-in cross reference correction and high accuracy. In this work, a novel polymer carbon nanodots (PCNDs) prepared from a facile one-pot hydrothermal procedure using readily available l-tryptophan and l-phenylalanine as precursors, showed excellent aqueous solubility and blue fluorescence property with a high quantum yield of 29%. Moreover, the PCNDs was demonstrated to be a robust luminophore with electrochemiluminescence (ECL) efficiency of 43% was achieved by using K2S2O8 as a coreactant. The spooling ECL spectroscopy was employed to take insight into excited states responsible for the potential-dependent ECL emissions. Most importantly, when introduced into construction of the fluorescence and ECL dual mode sensing platform, for the first time, the PCNDs displayed prominent performance for the detection of ferric ions (Fe3+). The ferric ions could be quantified ranging from micromolar to millimolar with a detection limit of 0.22 and 5.3 µM, respectively. Such a dual-functional sensing platform also exhibits excellent selectivity, reproducibility and stability. Results from this work indicate that PCNDs showing great promise as a bright luminophore for the fabrication of low-cost, high-performance dual-signal readout platforms for ferric ions determination.

Near-Infrared Electrogenerated Chemiluminescence from Simple Copper Nanoclusters for Sensitive Alpha-Fetoprotein Sensing.

Exploiting low cost, water-soluble, and near-infrared (NIR) emissive electrochemiluminophores (ECLphores) is significantly important for biological applications. In this study, bright and NIR electrogenerated chemiluminescence (ECL) emissive copper nanoclusters (Cu NCs) were synthesized through a facile one-pot wet chemical reduction method. ECL properties of obtained Cu NCs were examined in the presence of potassium persulfate, resulting in maximum intensity at 735 nm, at least 135 nm red-shifted with respect to all other Cu NCs. Electrochemistry, photoluminescence (PL), and spooling ECL spectroscopies were used to track NIR ECL emission of Cu NCs ascribed to the monomeric excited states. Due to the abundant binding sites of bovine serum albumin (BSA) to anchor target biomolecules, a sandwich-type ECL immunosensor was thus fabricated using such BSA-templated Cu NCs as tags and alpha fetoprotein antigen (AFP) as a model protein for the first time. Without assisting any signal amplification strategies, the proposed NIR ECL biosensor exhibited a wide linear range (1-400 ng mL-1) and low detection limit (0.02 ng mL-1) as well as superior selectivity and reproducibility and was successfully applied in real human serum sample determination. This work sets the stage for the development of novel non-noble metal nanoclusters for large-scale and emerging nanotechnology applications.

Signal Amplification Strategy Using Atomically Gold-Supported VO2 Nanobelts as a Co-reaction Accelerator for Ultrasensitive Electrochemiluminescent Sensor Construction Based on the Resonance Energy Transfer Platform.

Luminol, as a classical luminophore, plays a crucial role in electrochemiluminescence (ECL). However, the traditional luminol-H2O2 ECL system suffers from the self-decomposition of H2O2 at ambient temperature, which hinders its further application in quantitative analysis. In this work, for the first time, we developed atomically gold-supported two-dimensional VO2 nanobelts (Au/VO2) as an advanced co-reaction promoter to speed up the reduction of dissolved oxygen to superoxide radicals (O2•-), which react with the luminol anion radical and greatly promote the ECL emission. The ECL resonance energy transfer (ECL-RET) between the hollow manganese dioxide nanospheres and luminol results in a conspicuously decreased ECL signal response, and in the presence of glutathione (GSH), effective redox reaction between manganese dioxide and GSH restores the ECL signal. As a consequence, the designed sensor based on ECL-RET-assisted Au/VO2 signal amplification showed outstanding performance for "signal-on" detection of GSH in the concentration range of 10-3 to 10-10 M, and the detection limit was as low as 0.03 nM. The ECL sensor displayed excellent specificity and was successfully utilized to target GSH in real human serum samples. Importantly, this work not only highlights a powerful avenue for constructing an ultrasensitive ECL sensor for GSH but also provides some inspiration for the further design of high-performance co-reaction accelerators using the ECL technique.

Tailoring the Electronic Metal-Support Interactions in Supported Atomically Dispersed Gold Catalysts for Efficient Fenton-like Reaction.

The atomically dispersed metal is expected as one of the most promising Fenton-like catalysts for the degradation of recalcitrant organic pollutants (ROPs) by the strong "electronic metal-support interactions" (EMSIs). Here, we develop an atomically dispersed metal-atom alloy made by guest Au atoms substitute host V atoms in the two-dimensional VO2 (B) nanobelt support (Au/VO2 ) to activate Fenton-like oxidation for elimination of ROPs. The 2D nanobelt structure enlarges the exposure of atomically Au thus increasing the number of active sites to absorb more S2 O8 2- ions. And the EMSIs regulate the charge density in Au atoms to present positive charge Au+ , lowering the energy barrier of S2 O8 2- decomposition to produce SO4 .- . The Au/VO2 catalyst possesses excellent durable and reliable characteristics and exhibits record-breaking efficiency with TOF as high as 21.42 min-1 , 16.19 min-1 , and 80.89 min-1 for rhodamine, phenol, and bisphenol A degradation, respectively.

Aggregation-Induced Electrochemiluminescence of Tetraphenylbenzosilole Derivatives in an Aqueous Phase System for Ultrasensitive Detection of Hexavalent Chromium.

Herein, aggregation-induced electrochemiluminescence (AIECL) of tetraphenylbenzosilole derivatives in an aqueous phase system with the participation of a co-reactant was systematically investigated for the first time. All organics that we studied exhibit excellent stability and dramatically enhanced electrochemiluminescence (ECL) and photoluminescence (PL) emission when the water fraction increases. The influence of substituents in the structure of tetraphenylbenzosilole derivatives on AIECL performance was proved by fluorescence, cyclic voltammetry, and related theoretical calculation. Among them, 2,3-bis(4-cyanophenyl)-1,1-diphenyl-benzosilole (TPBS-C) with strong electron-withdrawing cyano groups exhibits the best ECL behavior with the highest ECL efficiency (184.36%). The strongest ECL emission of TPBS-C not only stems from the aggregated molecules that restrict the intramolecular motion of peripheral phenyl groups, which inhibits the nonradiative transition, but also comes from the fact that TPBS-C has the lowest reduction potential, and twice the reduction process of TPBS-C occurs to produce more anion radicals (TPBS-C·-). Significantly, the ECL sensor based on TPBS-C nanoaggregates exhibits excellent detection performance for toxic Cr(VI) with a wide linear range from 10-12 to 10-4 M and an extremely low detection limit of 0.83 pM. This work developed an efficient luminophore with unique AIECL properties and realized the ultrasensitive detection of Cr(VI) in the aqueous phase system.

How household chaos affects social withdrawal of rural children: the indirect role of executive function and receptive language ability.

Executive function (EF) and receptive language ability play an important role in the relationship between household chaos and social withdrawal. Young children are neglected in household chaos research and suffer from the negative outcomes of households in China. However, few studies have focused on the relationship between household chaos and social withdrawal in young Chinese children and the chain mediating effect of EF and receptive language ability. This study included 922 preschool-age children (62.58 ± 8.03 months) and their primary caregivers and their teachers were recruited from 21 rural preschools in Guangdong Province in China. Our results show a positive direct effect of household chaos and social withdrawal. Furthermore, an indirect sequential effect of household chaos and social withdrawal on EF and receptive language ability was found. Our findings (a) highlight the significance of paying more attention to household chaos and revealing a better understanding of the effect of EF and receptive language ability on households at an early age and (b) indicate that interventions should be provided to improve the home environment when children are young.