Latest ArticlesIt is of great significance to construct organic circularly polarized luminescence systems (CPL) with large luminescence dissymmetry factors (glum) for practical applications. Here we report organic CPL systems constructed by merging triplet-triplet annihilation upconversion chromophores in cellulose matrices. The chirality of the matrix is transferred to the achiral chromophores of photon upconversion and then the multistep energy transfer processes of upconversion amplify glum. The glum value of upconversion CPL in the left-handed ethyl cellulose and the right-handed (acetyl) ethyl cellulose are up to +0.1 and −0.15, respectively. The study provides a straightforward approach for constructing solid organic upconversion CPL materials with large glum, which may expand the application potentials of organic chiroptical materials.
Alkaline phosphatase (ALP) activity assay is not only significant to the clinical diagnosis of some related disease, but also momentous to the construction of ALP-based enzyme-linked immunosorbent assay (ELISA). Herein, for the first time, we have discovered that ascorbic acid (AA) can specially react with N-methylethylenediamine (N-MEDA) to generate fluorescent non-conjugated polymer dots (NCPDs) under mild conditions. On the basis of the AA-responsive emission and ALP-catalyzed hydrolysis of ascorbic acid 2-phosphate (AA2P) to AA, we have exploited a fluorometric ALP activity assay with high sensitivity and selectivity. Furthermore, by means of conventional ALP-based ELISA platform, a conceptual fluorescent ELISA has been constructed and applied in the potential clinical diagnosis, during which cardiac troponin I (cTnI), a well-established biomarker of acute myocardial infarction, has been chosen as the model target. We envision that such original fluorescent NCPDs generation-enabled ELISA could become a versatile tool in biochemical sensing and medical diagnosis in the future.
Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valuable chiral polycyclic indolines. However, these reactions have been mostly limited to transition-metal catalysts, and the related chiral Brønsted acid catalysis has been scarcely reported. Herein, we disclose a chiral phosphoric acid-catalyzed asymmetric dearomatization of indolyl ynamides by direct activation of alkynes. This metal-free method enables the practical and atom-economical construction of an array of valuable chiral polycyclic indolines in moderate to good yields with high enantioselectivities
In recent years, nanozymes have received more and more attention, but the low activity limits the development of nanozymes. Therefore, the design and development of efficient nanozymes is still a major challenge for researchers. Herein, the Fe,N co-doped ultrathin hollow carbon framework (Fe,N-UHCF) exhibit ultra-high peroxidase-like activity. The specific activity of Fe,N-UHCF nanozyme is as high as 36.6 U/mg, which is much higher than almost all of other reported nanozymes. In practical applications, the Fe,N-UHCF show good antibacterial effects.
A nickel-catalyzed direct hydromonofluoromethylation of unactivated olefins with industrial raw fluoroiodomethane is developed, furnishing various primary alkyl fluorides in a step-economic manner. The key factor to success is the use of pyridine-oxazoline as ligand and (MeO)2MeSiH as the hydrogen source. This transformation demonstrates high efficiency, mild conditions, good functional-group compatibility and great potential in the drug discovery.
As important emerging contaminants, antibiotics have caused potential hazards to the ecological environment and human health due to their extensive production and consumption. Among various techniques for removing antibiotics from wastewater, H2O2-based advanced oxidation processes (AOPs) have received increasing attention due to their fast reaction rate and strong oxidation capability. Hence this review critically discusses: (ⅰ) Recent research progress of AOPs with the addition of H2O2 for antibiotics removal through different methods of H2O2 activation; (ⅱ) recent advances in AOPs that can in-situ generate and activate H2O2 for antibiotics removal; (ⅲ) H2O2-based AOPs as a combination with other techniques for the degradation and mineralization of antibiotics in wastewater. Future perspectives about H2O2-based AOPs are also presented to grasp the future research trend in the area.
The normal operation of lysosome, mitochondria, Golgi apparatus and endoplasmic reticulum plays a significant role in maintaining cell homeostasis. Reflecting the state and function of lysosomes, viscosity is a pivotal parameter to assess the stability of microenvironment. Herein, based on TICT mechanism, a new NIR pH-dependent fluorescent probe DCIC with push-pull electronic moiety was synthesized to identify the lysosomes viscosity. In viscous media, DCIC was highly sensitive to viscosity, fluorescence intensity increased by 180 times as viscosity increased from 1.0 cp to 438.4 cp. In addition, DCIC have high localization ability for lysosome, mitochondria, Golgi apparatus, and endoplasmic reticulum and can monitor lysosomal viscosity fluctuations with laser confocal microscopy.
Highly branched poly(β-amino ester)s (HPAEs) have shown their great promise in gene delivery. However, their broad molecular weight distribution (MWD) poses an additional challenge to the mechanistic understanding of the influence of molecular weight (MW) on their gene transfection activity. Using a stepwise precipitation strategy, HPAEs were fractionated. It is shown that MW has a significant effect on the transfection activity and cytotoxicity of HPAEs. The intermediate MW mediates higher transfection efficiency while maintaining high cell viability. Mechanistic studies show that the intermediate MW confers stronger DNA binding affinity to HPAEs, leading to the formulation of polyplexes with a relatively smaller size and more positive zeta potential. This study not only suggests a simple strategy to fractionate HPAEs with narrow MWD but also provides new insights into understanding the structure-property relationship, which would facilitate the clinical translation of HPAEs in gene therapy.
Understanding the regulatory mechanism of self-assembly processes is a necessity to modulate nanostructures and their properties. Herein, we have studied the mechanism of self-assembly in the C3 symmetric 1, 3, 5-benzentricarboxylic amino acid methyl ester enantiomers (TPE) in a mixed solvent system consisting of methanol and water. The resultant chiral structure was used for chiral recognition. The formation of chiral structures from the synergistic effect of multiple noncovalent interaction forces was confirmed by various techniques. Molecular dynamics simulations were used to characterize the time evolution of TPE structure and properties in solution. The theoretical results were consistent with the experimental results. Furthermore, the chiral structure assembled by the building blocks of TPE molecules was highly stereoselective for diamine compounds.
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