Stable Fluorescence of Eu3+ Complex Nanostructures Beneath a Protein Skin for Potential Biometric Recognition.

We designed and realized highly fluorescent nanostructures composed of Eu3+ complexes under a protein coating. The nanostructured material, confirmed by photo-induced force microscopy (PiFM), includes a bottom fluorescent layer and an upper protein layer. The bottom fluorescent layer includes Eu3+ that is coordinated by 1,10-phenanthroline (Phen) and oleic acid (O). The complete complexes (OEu3+Phen) formed higher-order structures with diameter 40-150 nm. Distinctive nanoscale striations reminiscent of fingerprints were observed with a high-resolution transmission electron microscope (HRTEM). Stable fluorescence was increased by the addition of Eu3+ coordinated by Phen and 2-thenoyltrifluoroacetone (TTA), and confirmed by fluorescence spectroscopy. A satisfactory result was the observation of red Eu3+ complex emission through a protein coating layer with a fluorescence microscope. Lanthanide nanostructures of these types might ultimately prove useful for biometric applications in the context of human and non-human tissues. The significant innovations of this work include: (1) the structural set-up of the fluorescence image embedded under protein "skin"; and (2) dual confirmations of nanotopography and unique nanofingerprints under PiFM and under TEM, respectively.

The transcription factor AtGLK1 acts upstream of MYBL2 to genetically regulate sucrose-induced anthocyanin biosynthesis in Arabidopsis.

BACKGROUND: The regulation of anthocyanin biosynthesis by various factors including sugars, light and abiotic stresses is mediated by numerous regulatory factors acting at the transcriptional level. Here experimental evidence was provided in order to demonstrate that the nuclear GARP transcription factor AtGLK1 plays an important role in regulating sucrose-induced anthocyanin biosynthesis in Arabidopsis. RESULTS: The results obtained using real-time quantitative PCR and GUS staining assays revealed that AtGLK1 was mainly expressed in the green tissues of Arabidopsis seedlings and could be induced by sucrose. The loss-of-function glk1 glk2 double mutant has lower anthocyanin levels than the glk2 single mutant, although it has been determined that loss of AtGLK1 alone does not affect anthocyanin accumulation. Overexpression of AtGLK1 enhances the accumulation of anthocyanin in transgenic Arabidopsis seedlings accompanied by increased expression of anthocyanin biosynthetic and regulatory genes. Moreover, we found that AtGLK1 also participates in plastid-signaling mediated anthocyanin accumulations. Genetic, physiological, and molecular biological approaches demonstrated that AtGLK1 acts upstream of MYBL2, which is a key negative regulator of anthocyanin biosynthesis, to genetically regulate sucrose-induced anthocyanin biosynthesis. CONCLUSION: Our results indicated that AtGLK1 positively regulates sucrose-induced anthocyanin biosynthesis in Arabidopsis via MYBL2.

2D/2D Heterojunction of R-scheme Ti3C2 MXene/MoS2 Nanosheets for Enhanced Photocatalytic Performance.

Combination of two-dimensional (2D) materials and semiconductors is considered to be an effective way for fabricating photocatalysts for solving the environmental pollution and energy crisis. In this work, novel 2D/2D heterojunction of R-scheme Ti3C2 MXene/MoS2 nanosheets is successfully synthesized by hydrothermal reaction. The photocatalytic activity of the Ti3C2 MXene/MoS2 composites is evaluated by photocatalytic degradation and hydrogen evolution reaction. Especially, 0.5 wt% Ti3C2 MXene/MoS2 sample exhibits optimum methyl orange (MO) degradation and H2 evolution rate of 97.4% and H2 evolution rate of 380.2 µmol h-1 g-1, respectively, which is attributed to the enhanced optical absorption ability and increased specific surface area. Additionally, Ti3C2 MXene coupled with MoS2 nanosheets is favorable for improving the photocurrent response and reducing the electrochemical impedance, leading to the enhanced electron transfer of excited semiconductor and inhibition of charge recombination. This work demonstrates that Ti3C2 MXene could be a promising carrier to construct 2D/2D heterojunction in photocatalytic degradation and hydrogen evolution reaction.

Construction of BPQDs/Ti3C2@TiO2 Composites with Favorable Charge Transfer Channels for Enhanced Photocatalytic Activity under Visible Light Irradiation.

Design and construction of double heterojunction is favorable to improve the separation and migration efficiency of photogenerated carriers, thus preferably solve the problems of environmental pollution and energy crisis. Herein, TiO2 nanoparticles (NPs) are in-situ grown on highly conductive Ti3C2 nanosheets via low-temperature hydrothermal strategy, and then black phosphorus quantum dots (BPQDs) are introduced on the surface of TiO2 NPs. Under hydrothermal temperature 120 °C, the BPQDs/Ti3C2@TiO2 photocatalyst exhibits remarkable enhanced photocatalytic degradation of methyl orange (MO) and hydrogen evolution reaction (HER) compared with BPQDs/Ti3C2 and Ti3C2@TiO2 composites. Enhanced photocatalytic activity can be attributed to (i) the BPQDs with tunable bandgaps are deposited on the TiO2 NPs to form intimate heterojunction, which facilitates the electrons transfer from the conduction band (CB) of BPQDs to the CB of TiO2; (ii) the electrons quickly migrate from CB of TiO2 NPs to the Ti3C2 nanosheets with excellent electronic conductivity via electron transfer channel, which is beneficial to prolong the lifetime of electrons and hinder the recombination of photogenerated carriers; (iii) the enhanced visible light absorption and enlarged specific surface area of BPQDs/Ti3C2@TiO2 further accelerate the photocatalytic reaction. This work emphasizes the essential role of quantum dots in the construction of double heterojunction and the potential application of Ti3C2 MXene for improving photocatalytic activity.