Latest ArticlesHerein, we report the dynamic kinetic resolution asymmetric acylation of γ-hydroxy-γ-perfluoroalkyl butenolides/phthalides catalyzed by amino acid-derived bifunctional organocatalysts, and a series of ketals were obtained in high yields (up to 95%) and excellent enantioselectivities (up to 99%). In terms of synthetic utility, the reaction can be performed on a gram scale, and the product can be converted into potential biological nucleoside analog.
Intracellular redox homeostasis is of indispensable importance in pathophysiology. In order to maintain the balance of the redox state within the cell, reactive oxygen species (ROS) and reactive sulfur species (RSS) react and transform with each other, and their levels also directly reflect the degree of oxidative stress and disease. Hypochlorous acid (HClO) and cysteine (Cys) usually co-exist in organisms, interacting with each other in many important physiological processes and synergistically maintaining the dynamic redox balance in the body. To understand the relevance and pathophysiological effects of these two signaling molecules in oxidative stress, unique fluorescence imaging tools are required. Herein, we designed and developed a dual-channel fluorescent probe HP, for the individual and continuous detection of HClO and Cys. This probe could simultaneously monitor the changes in the concentrations of HClO and Cys in cells, and was characterized by a fast response, high sensitivity and high selectivity, especially compared with glutathione (GSH) and homocysteine (Hcy), the probe had a good specificity for Cys. Importantly, probe HP successfully observed dynamic changes in HClO- and Cys-mediated redox status in the oxygen-glucose deprivation/reperfusion (OGD/R) model of HeLa cells and dynamically monitored fluctuations in endogenous HClO levels in lipopolysaccharides (LPS)-induced peritonitis mice.
Most photodynamic therapies (PDT) rely on reactive oxygen species (ROS) produced by type Ⅱ mechanisms. However, since the production of type Ⅰ ROS is not limited by oxygen content, making it more favorable for antimicrobial phototherapy in complex microenvironments. Herein, we report a substituent cationization design strategy that not only improves the hydrophilicity of the prepared phthalocyanine molecule, but also promotes the electron transfer process in the photosensitizer, resulting in the strong type Ⅰ photodynamic effect of the phthalocyanine self-assembled photosensitizer to efficiently generate O2•- under both normal and hypoxic conditions. This in combination with its excellent bacteria recognition capability derived from the cationic part on its surface and intrinsic photothermal therapy effect of the phthalocyanine macrocycle endows the phthalocyanine self-assembled photosensitizer with excellent phototherapeutic antimicrobial properties in preclinical models, effectively promoting the wound healing process. This work provides a promising strategy for designing efficient multi-mode photosensitizers.
Human β-galactosidase (β-gal) is recognized as a crucial biomarker for evaluating senescence at the cellular and tissue levels in humans. However, tools to precisely track the endogenous β-gal are still limited. Herein, we present two novel self-calibrating β-gal probes 7a and 7b which were constructed on a unique green/red dual-emissive fluorescence platform. The two probes inherently exhibited a stable green fluorescence signal impervious to β-gal activity, serving as a reliable internal reference. They also displayed a progressively diminishing red fluorescence signal with the increasing of β-gal expression levels. The dual behavior endows them with self-calibration capacity and then renders excellently selective and sensitive for precisely monitoring β-gal activity. Notably, compared with E. coli β-gal, the two probes are more effectively response to A. oryzae β-gal homologous to human β-gal, indicating their unique species-selectivity. Furthermore, 7a was validated for its effectiveness in determining senescence-associated β-galactosidase (SA-β-gal) expression in senescent NRK-52E and HepG2 cells, underscoring its practical applicability in senescence research.
The prototype material, Li1.23Ru0.41Ni0.36O2, is proposed to gain the deep and comprehensive understanding of chemical and structural changes of the novel layered/rocksalt intergrown cathodes. Synchrotron-based X-ray absorption spectra and resonant inelastic X-ray scattering reveal that both cationic and anionic redox evolves in the charge compensation process of the intergrown material, while synchrotron-based extended X-ray fine structure spectra and in situ X-ray diffraction measurements demonstrates that the intergrown material undergoes minimal local- and long-range structural variations at deep de/lithiation. This work highlights the great potential of the intergrown structure to inspire the design of advanced cathode materials for lithium-ion batteries.
Multimodal bioorthogonal small molecule probes play a pivotal role in drug-focused biomedical research. However, existing drug tracking and imaging techniques face obstacles in living organisms, hindering precise drug localization and target protein capture. Herein, we introduced a multimodal probe named 1-(azidomethyl)pyrene-4,5–dione (AMPD). The probe incorporates adjacent dione structures at the pyrene core. AMPD selectively interacts with oxygen-rich alkene-labeled drug molecules under ice-blue LED light exposure, producing specific fluorescence emission and enabling in vivo tracking and flow cytometry sorting. A methyl azide group was also introduced at the pyrene core to help efficiently enrich target proteins via click chemistry with alkyne-functionalized beads. AMPD demonstrates exceptional biocompatibility, rendering it highly suitable for visual photo-triggered tracking studies. Combined with metabolic labeling using an oxygen-rich alkene-tagged drug molecule probe, AMPD is effective for live animal, tissue, cellular, and in-gel imaging, as well as target protein identification through magnetic capture. With its versatile capabilities, AMPD enhances our comprehension of drug-target interactions at the in vivo level and expedites the process of drug discovery.
The insufficient F(III)/Fe(II) cycling rate resulted from high combination of photogenerated carriers severely hinders the photo-Fenton activity. In this work, 0 dimensional α-Fe2O3 nanoclusters decorated TiO2 heterojunction (FT-x) was prepared via in-situ phase transformation strategy. FT-200 exhibited the optimal photo-Fenton activity for 2,4-dichlorophenol degradation with the kinetic rate constant reaching 1.0806 min−1 under low H2O2 dosage (1 mmol/L), which was 126.1 and 202.8 times higher than that of TiO2 and α-Fe2O3. Radical quenching experiments and electron spin resonance spectra proved that ·OH was the leading reactive specie. The enhanced photo-Fenton activity was attributed to the accelerated F(III)/Fe(II) cycling rate induced by the direct Z-Scheme charge transfer mechanism. Benefiting from the abundant ·OH production, the dechlorinate ratios and mineralization ratios of multiple chlorophenol pollutants (2,4-dichlorophenol, 4-chlorophenol, 2,4,6-trichlorophenol) all exceeded 98%. The biotoxicity of chlorophenol wastewater was greatly reduced after the treatment by Light/H2O2/FT-200 system. Overall, this work constructed a low-cost and highly efficient photo-Fenton system for refractory organic wastewater treatment.
The design of pnictide nonlinear optical crystals is quite different from chalcogenide and oxide those, in which a new paradigm need be developed to regulate the band gap, one of key optical parameters. In this work, two non-centrosymmetric halidepnictides, [Cd2P]2[CdBr4] (CPB) and [Cd2As]2[CdBr4] (CAB) were reported. The complete octet binding electrons of pnictogens were constructed by four Cd-P polar covalent bonds under the anchoring effect of halogens, creating an extremely flat valence band maximum with band dispersion of only 0.17 eV. As expected, the balance of the covalency and ionicity in CPB and CAB was successfully realized, leading to a wide band gap of 2.58 eV and 1.88 eV. Remarkably, CPB not only has a widest band gap among Cd-containing pnictides, but also exhibits a SHG effect of 1.2 × AgGaS2, moderate birefringence (0.088@visible light and calcd. 0.043@2050 nm) and a wide IR transmission range. This is the first time that the octet binding electrons construction strategy was utilized to design non-diamond like NLO pnictides with excellent performances.
Highly active cathode catalysts for efficient formation/decomposition of Li2O2 are essential for the performance improvement of lithium-oxygen batteries (LOBs). In this study, a grain-refining Co0.85Se catalyst with a lattice spacing of 2.69 Å of (101) plane closely matching with the (100) plane (2.72 Å) of Li2O2 was applied for high-performance LOBs. Highly (101) plane exposed Co0.85Se@CNT was synthesized by a simple one-pot hydrothermal method. The Co0.85Se with the lattice matching effect not only led to the efficient conversion and polarized growth of Li2O2, but also prevented the formation of byproducts. Density functional theory (DFT) calculations reveal that Co0.85Se (101) plane has the intrinsic catalytic ability to generate/decompose Li2O2 during ORR/OER process, due to its homogeneous electron distribution, suitable adsorption energy, and promoted Li2O2 growth kinetics. As a consequence, the (101) plane highly exposed Co0.85Se@CNT-80 electrode exhibited remarkable cycle stability over 2400 h at 100 mA/g and 290 cycles at 500 mA/g, which is about 2 times longer than other electrodes.
The anti-oxidative characteristic and immunosuppressive microenvironment contribute to a high resistance of tumor to many treatments. In this work, a glutathione (GSH)-responsive metal-coordinated oxidative stress amplifier (designated as CuPA) is fabricated to suppress tumor growth through elevating the cellular level of reactive oxygen species (ROS) and eliminating M2 macrophages. Among which, cooper ion (Cu2+) is capable of coordinating with thioredoxin (Trx) inhibitor of PX-12 and signal transducer and activator of transcription 6 (STAT6) inhibitor of AS1517499 with the assistance of distearoyl phosphoethanolamine-PEG2000 (DSPE-PEG2000), which can extensively increase the stability to enhance drug delivery in vitro and in vivo. Furthermore, CuPA can upregulate intracellular ROS to cause tumor cell death through restraining Trx and degrading GSH. Also, CuPA-mediated STAT6 inhibition results in the elimination of M2 macrophage to reverse the immunosuppressive tumor microenvironment. Finally, the elevated oxidative stress and increased immune activation amplify the synergistic antitumor effect without causing obvious side effect. This work provides a new sight for synergistic tumor suppression through chemo-immunotherapy in consideration of the complex resistant tumor microenvironment.
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