Latest ArticlesDeveloping a high-quality photoelectrode for photoelectrochemical applications is still an ongoing challenge. In this study, we prepared the g-C3N4 film on the indium tin oxide (ITO) glass through conventional coating, liquid-based growth, in-situ calcination, and vapor deposition methods, respectively. These electrodes were characterized and used as photoanodes to degrade methylene blue (MB) in water. Among these methods, the in-situ calcination method was most appropriate for preparing the continuous and organized g-C3N4 film electrodes with uniform g-C3N4 coverage and strong adhesion to the ITO substrate. It also had the highest activity in the photocatalytic (PC), electrochemical (EC), and photoelectrocatalytic (PEC) degradation processes of MB. In the PEC reaction, at an applied potential of 1.0 V and a light intensity of 0.96 W/cm2, the removal rate of MB was 62.5%, which was much higher than those in the PC and EC reactions. The high degradation rate was due to the synergistic effect of PEC degradation, wherein the PC and EC reactions promote and optimize each other. In the PC reaction, MB was degraded by −CH3 elimination, while the EC degradation pathway mainly included the conversion of sulfhydryl into sulfoxide and the opening of the central aromatic ring. Both methyl loss and aromatic ring opening occurred in the PEC reaction. Moreover, some monocyclic compounds were formed, and MB showed more complete degradation in the PEC reaction.
The exploration of novel photo/thermal-responsive nonvolatile memorizers will be beneficial for energy-saving memories. Herein, new <110> -oriented perovskites using single template melamine, i.e., [(MLAI-H2)(PbX4)] (X = Br (α-1), Cl (α-2), MLAI = melamine) have been prepared and their structures upon irradiation of visible light have been investigated. They have been fabricated as nonvolatile memory devices with structures of ITO/[(MLAI-H2)(PbX4)]/PMMA/Ag (device-1: X = Br, device-2: X = Cl), which can exhibit unique visible light-triggered binary nonvolatile memory performances. Interestingly, the silent or working status can be monitored by visible chromisms. Furthermore, the light-triggered binary resistive switching mechanisms of these ITO/[(MLAI-H2)(PbX4)]/PMMA/Ag memory devices have been clarified in terms of EPR, fluorescence, and single-crystal structural analysis. The presence of light-activated traps in <110> -oriented [(MLAI-H2)(PbX4)] perovskites are dominated in the appearance of light-triggered resistive switching behaviors, based on which the inverted internal electrical fields can be established. According to the structural analysis, the more distorted PbX6 octahedra, higher corrugated <110> -oriented perovskite sheets, and more condensed organic-inorganic packing in Br-containing perovskite are beneficial for the stabilization of light-activated traps, which lead to the better resistive switching behavior of device-1. This work can pave a new avenue for the establishment of novel energy-saving nonvolatile memorizers used in aerospace or military industries.
Potassium-ion batteries (PIBs) have attracted tremendous attention for large-scale energy storage fields based on abundant potassium resources. Graphite is a promising anode material for PIBs due to its low potassium ion intercalation voltage and mature industrialized preparation technology. However, the inability of graphitic structures to endure large volume change during charge/discharge cycles is a major limitation in their advancement for practical PIBs. Herein, a soft carbon-coated bulk graphite composite is synthesized using PTCDA as a carbon precursor. The PTCDA-derived soft carbon coating layer with large interlayer distance facilities fast potassium ion intercalation/extraction in the BG@C composite and buffers severe volume change during the charge/discharge cycles. When tested as anode for PIBs, the composite realizes enhanced rate capability (131.3 mAh/g at 2 C, 1 C = 279 mA/g) and cycling performance (capacity retention of 76.1% after 150 cycles at 0.5 C). In general, the surface modification route to engineer graphite anode could inherently improve the electrochemical performance without any structural alteration.
The regulation of the basic properties of atom-economic catalysts at the atomic scale and atomic-level insights into the underlying mechanism of catalysis are less explored. We engineer the surface of vertical immobilized MoS2 on dispersible TiO2 nanofibers via atomic subtraction to precisely manipulate active sites at the atomic level. The photocatalytic performances of TiO2@MoS2 after H2 reduction towards the hydrogen production under visible light irradiation (> 420 nm) are about 4 times that of TiO2@MoS2 before H2 reduction. Importantly, the enhanced stability of TiO2@MoS2 lasts for at least 30 h. Promising catalytic activity that is attributed to omnidirectional exposed active sites located defects, edges, corners that are transformed from the subtractive atomic sites could be exhumed comprehensively. This work will provide an intriguing and effective approach on tuning electronic structures for optimizing the catalytic activity at the atomic level by atom elimination strategy. To get rid of a few atomics on the surface of atomically-thin MoS2 nanosheet could be a prudent avenue for enabling the basal plane of MoS2 catalytically active.
5-Formylcytosine (5fC), as an important epigenetic modification, plays a vital role in diverse biological processes and multiple diseases by regulating gene expression. Owing to the extremely low abundance of 5fC in all mammalian tissues and high structural similarity with other cytosine derivatives, the precise and sensitive detection of 5fC is challenging. Herein, a photo-elutable and template-free isothermal amplification strategy has been proposed for the sensitive detection of 5fC in genomic DNA based on 5fC-specific biotinylation, enrichment, photocleavage, and terminal deoxynucleotidyl transferase (TdT)-assisted fluorescence signal amplification, which is termed 5fC-PTIAS. By introducing the highly specific chemolabeling and the one-step photoelution processes, this strategy possesses a minimal nonspecific background as well as a much higher amplification efficiency. With the high signal-to-noise ratio, this strategy can achieve the accurate quantification of 5fC in various biological samples including mouse brain, kidney, and liver, with a limit of detection (LOD) of 0.025‰ in DNA (S/N = 3). These results not only confirm the widespread distribution of 5fC but also indicate its significant variation in different tissues and ages. The bisulfite- and mass spectrometry-free strategy is highly sensitive, selective, and easily mastered, holding great promise in detecting other epigenetic modifications with much lower levels.
A variety of luminol derivatives with N- and O-substitution have been synthesized with broad functional group tolerance. O-esterification has been demonstrated for the first time as a promising way to prepare enhanced CL reagents for sensing hemin, bloodstain and horseradish peroxidase (HRP). The most effective analogue with a deuterated acetyl group exhibited greater potential than luminol for bloodstain imaging and HRP imaging in western blotting (WB). In addition, O-etherification can greatly suppress CL signal that has been applied to design a CL probe for β-glucosidase (β-Glu). This study offers important and useful information regarding the luminol modification and shows great potential to use O-substituted analogues for enhanced CL analysis.
Ribosomal RNAs (rRNAs) provide the structural framework of ribosomes and play critical roles in protein translation. In ribosome biogenesis, rRNAs acquire various modifications that can influence the structure and catalytic activity of ribosomes. However, rRNA modifications in plants have yet to be fully defined. Herein, we proposed a method to purify rRNAs by a successive isolation with different strategies, including polyA-based mRNA depletion and agarose gel electrophoresis-based purification, with which highly pure rRNAs could be obtained. In addition, we developed a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method to systematically profile and characterize modifications from the isolated highly pure plant 18S rRNA and 25S rRNA. LC-ESI-MS/MS analysis showed that 10 and 12 kinds of modifications were present in plant 18S rRNA and 25S rRNA, respectively. Notably, among these identified modifications, 2 kinds of modifications of N2,N2-dimethylguanosine (m2,2G) and N6,N6-dimethyladenosine (m6,6A) in 18S rRNA, and 4 kinds of modifications of m2,2G, m6,6A, N7-methylguanosine (m7G) and 3-methyluridin (m3U) in 25S rRNA, were first reported to be present in plants. Moreover, exposure of Arabidopsis thaliana to cadmium (Cd) led to significant changes of modifications in both 18S rRNA and 25S rRNA of plants, indicating that rRNA modifications play important roles in response to environmental stress. The discovery of new modifications in plant rRNAs improves the spectra of plant rRNA modifications and may promote the investigation of the functional roles of plant ribosomes in regulating gene expression.
Development of sensitive and accurate methods for sialic acid (SA) determination is of great significance in early cancer diagnosis. Here, a colorimetric-assisted Photoelectrochemical (PEC) sensor was constructed for SA detection based on the two pairs of cis-diol groups in SA molecule. With the specific recognition of SA via the two pairs of cis-diol groups, the prepared gold-modified Bi2S3 (Au NPs@Bi2S3) and metal organic framework (Au@PCN-224) were introduced to the electrode and formed a sandwich structure. Based on the properties of inert electroconductivity and nanozyme of the PCN-224, dual-readout of photocurrent and visualization was achieved with the presence of 3, 3′, 5, 5′-tetramethylbenzidine (TMB). Moreover, to intensify the visualization signal, Ce3+ was employed as the mediator to boost the catalysis capability by transferring energy from PCN-224 surface to the whole system. With the unique SA recognition and the mediation of Ce3+, both the photocurrent and the visualization signals sensitively responded with the SA concentration linearly. The present method showed greatly high sensitivity, selectivity and accuracy for SA detection with a limit of detection of 1.44 µmol/L and a wide linear range of 5–1000 µmol/L. This method provided a new promising platform for SA detection and a potential strategy for design of novel biosensors with dual-model readout.
Poly(ethylene glycol)-poly(lactic acid) block copolymer (PEG-PLA) is one of the most widely used biomedical polymers in clinical drug delivery owing to its biocompatibility and biodegradability. However, endowing PEG-PLA micelles with high drug loading, self-assembly stability and fast intracellular drug release is still challenging. Redox-responsive diblock copolymers (MPEG-SS-PMLA) of poly(ethylene glycol) and phenyl-functionalized poly(lactic acid) with disulfide bond as the linker are synthesized to prepare PLA-based micelles that demonstrate excellent colloidal stability and high Ru loading. Notably, MPEG-SS-PMLA achieved a remarkably high Ru loading efficiency of 84.3% due to the existence of strong π-π stacking between phenyl and Ru complex. MPEG-SS-PMLA exhibited good colloidal stability in physiological condition but quickly destabilized by reductive tumor microenvironment. Interestingly, about 74% of Ru complex was released under 10 mmol/L GSH concentration. Ru-loaded MEPG-SS-PMLA showed efficient delivery and release of Ru complex into MCF-7 cancer cells, achieving enhanced in vitro and in vivo antitumor activity of photodynamic therapy. This feasible functionalization method of MPEG-PLA has appeared to be a clinically viable platform for controlled delivery therapeutic agents and enhanced phototherapy.
The strong intrinsic Coulomb interactions of Frenkel excitons in crystalline carbon nitride (CCN) greatly limits their dissociation into electrons and holes, resulting in unsatisfactory charges separation and photocatalytic efficiency. Herein, we propose a strategy to facilitate excitons dissociation by molecular regulation induced built-in electric field (BIEF). The electron-rich pyrimidine-ring into CCN changes the charge density distribution over heptazine-rings to induce BIEF between melon chains. Such BIEF is sufficient to overcome the considerable exciton binding energy (EBE) and reduce it from 38.4 meV to 16.4 meV, increasing the excitons dissociation efficiency (EDE) from 21.5% to 51.9%. Our results establish a strategy to facilitate excitons dissociation through molecular regulation induced BIEF, targeting the intrinsic high EBE and low EDE of polymer photocatalysts.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
