Latest ArticlesUtilizing small molecules as markers for specific cells or organs within biosystems is a crucial approach for studying and regulating physiological processes. However, current tagging strategies, due to the presence of exposed highly reactive groups, suffer from drawbacks such as low tagging efficiency or insufficient spatial specificity, thereby diminishing their expected effectiveness. Consequently, there is a pressing need to develop a strategy capable of in situ labeling of active groups in response to cellular or in vivo stimuli, ensuring both high tagging efficiency and spatial specificity. In this work, we devised a strategy for releasing aldehyde groups activated by hypochlorous acid (HOCl). Compounds synthesized through this strategy can release the fluorophore methylene blue (MB) and aldehyde-based compounds upon HOCl activation. Given high reactivity of the released aldehyde group, it can effectively interact with macromolecules in biological systems, facilitating tagging and enabling prolonged imaging. To validate this concept, we further incorporated a naphthalimide structure with stable light emission to create SW-110. SW-110 can specifically respond to in vitro and endogenous HOCl, when release MB, it also releases naphthalimide fluorophore with highly reactive aldehyde group for tagging within cells. This strategy provides a simple but efficient strategy for proximity tagging in situ.
MicroRNA-133a (miRNA-133a) and cardiac troponin I (cTnI) are different-type crucial biomarkers of acute myocardial infarction (AMI), whose levels are great significance for AMI diagnosis and treatment. Herein, a novel photoelectrochemical-electrochemical (PEC-EC) dual-mode biosensing platform for dual-target assays of miRNA-133a and cTnI was developed. In which, a PEC-EC dual-mode sensing platform for miRNA-133a was constructed based on the changes of the photocurrent inhibition effect and the electrochemical signal of Fc on the Fc-hairpin DNA probe (Fc-HP)/ZnCdS-quantum dots (QDs)/ITO electrode. Furthermore, under magnetic separation and the specific interaction between cTnI and its aptamer, the N-doped porous carbon-ZnO polyhedra (NPC-ZnO)-hemin-capture DNA probe hybrid (NH-CP) was obtained and introduced to the Fc-HP/ZnCdS-QDs/ITO electrode via hybridization between NH-CP and Fc-HP. The hemin molecules encapsulated in NH-CP could effectively induce the photocurrent-polarity-switching of the Fc-HP/ZnCdS-QDs/ITO electrode and generate a new electrochemical signal originating from hemin. Thus, cTnI was assayed sensitively and selectively by the PEC-EC dual-mode biosensing platform. Here, Fc and hemin not only serve as the electrochemical indicators, but also respectively inhibit the photocurrent and switch the photocurrent polarity of ZnCdS-QDs. Furthermore, the proposed biosensing platform could be easily expanded to the detection of other multiplex-type biomarkers via the change of the sequences of the related DNA probes, implying its significant potential in clinical diagnosis and biological analysis.
In most Suzuki–Miyaura carbon-carbon cross-coupling reactions, the borabicyclo[3.3.1]nonane scaffold (9-BBN) only serves as an auxiliary facilitating the transmetalation step and thus is transformed into by-products. There are rare examples where the 9-BBN derivatives serve as the potentially diverse C8 building blocks in cross-coupling reactions. Herein, we report a cobalt-catalyzed migratory carbon-carbon cross-coupling reaction of the in situ formed 9-BBN ate complexes to afford diverse aryl- and alkyl-functionalized cyclooctenes. Preliminary mechanistic studies suggest the oxidation-induced cis-bicyclo[3.3.0]oct-1-ylborane is the key intermediate in this migratory cross-coupling reaction, which promotes the development of other diverse migratory cross-coupling of borate complexes.
Tuning the nanozyme′s activity and specificity is very crucial for developing highly sensitive sensors for various applications. Herein, selenium-doped porous N-doped carbon skeletons (Se/NC) nanozymes with highly specific peroxidase-like activity were synthesized by a MOF-pyrolysis-doping protocol. Se doping adjusted the electronic structure of NC by introducing more vacancies, defective carbon and graphitic N, and endowed the resultant Se/NC enhanced charge transfer and substrate affinity. The Se/NC exhibited specific peroxidase-mimicking activity and could catalyze 3,3′,5,5′-tetramethylbenzidine oxidation by H2O2. Density functional theory (DFT) calculations and experimental trials indicated that both Se=O and C–Se–C species were the main active sites of Se/NC. The C–Se–C bond is the main catalytic active site endowing Se/NC with the property of nanozyme, while the Se=O bond effectively enhances its affinity to H2O2 and accelerate H2O2 dissociation. The Se/NC showed an approximately 185-fold increase in peroxidase-like activity compared to NC. Based on the inhibition of the peroxidase-like activity of Se/NC by methimazole, a colorimetric sensor was developed to achieve its sensitive detection with 2 nmol/L of limit of detection. It was successfully used for detecting methimazole in real samples. Current Se doping strategy simplifies the fabrication process of high performance specific nanozyme and promises great potential for environmental analysis.
The fabrication of bioreceptor-free method for accurate and sensitive detection of ochratoxin A (OTA) in cereal is critical, but still a significant challenge to mitigate risks to food industries and public health. In this study, a smartphone-ratiometric fluorescence sensor for the ultrasensitive detection of OTA is developed based on a porphyrinic metal-organic framework and silica nanoparticle composite (Zr-MOF/SiNPs) away from the use of antibodies and aptamers. Due to the excellent recognition ability of Zr-MOF and good storage stability of SiNPs, OTA is detected by Zr-MOF/SiNPs with a wide linear range of 0.05–1000 ng/mL and low detection limit of 0.016 ng/mL. Moreover, the red–blue ratio values of the fluorescence images are extracted through the smartphone color recognizer application with a limit of detection of 1.74 ng/mL, lower than the permissible content of OTA in cereal prescribed by World Health Organization. This sensing platform has been successfully applied in maize samples with superior repeatability and satisfactory recoveries, providing a novel way for simple and label-free analysis of OTA in cereal.
In this work, we put forward a new and universal approach, i.e., cyanine ketone method, for fabricating meso–aryl heptamethine indocyanines, which is so simple that the treatment of the easy-to-get cyanine ketones with various aromatic lithium (ArLi), followed by acidification, could straightforwardly give rise to the products in one-pot way. Importantly, due to the strong nucleophilicity of ArLi, a series of bulky hydrophilic aromatic groups can be facilely integrated into the meso–position of heptamethine indocyanines, not only effectively inhibiting the undesired dye self-aggregation but also largely improving the water-solubility. Using one of anti-aggregation meso–aryl heptamethine indocyanines, we fabricated a dye-antibody conjugate for in vivo imaging tumor in a mouse model and achieved a high tumor-to-normal tissue ratio. The work laid a chemical foundation for constructing various meso–aryl heptamethine indocyanines, facilitating the advanced imaging and therapeutic applications in future.
The construction of triplet-to-singlet Förster resonance energy transfer (TS-FRET) systems has significantly contributed to the advancement of high-performance optoelectronic materials, particularly in the development of metal-free organic environmental afterglow materials. Despite these notable advancements, achieving highly efficient energy transfer between luminescent donor and acceptor molecules remains a formidable challenge. In this study, we present the utilization of cation-π interactions as an effective strategy to enhance TS-FRET efficiency, with the ultimate objective of further advancing fluorescence afterglow materials. Our results demonstrate that the cation-π interaction in 1D supramolecular nanorods (1D-SNRs) enhances the dipole-dipole coupling, a crucial parameter for regulating TS-FRET between the triplet state phosphorescent donor and singlet state fluorescent acceptor. As a result, we achieved an outstanding TS-FRET efficiency of up to 97%. Furthermore, the 1D-SNRs exhibit a long-lifetime afterglow property, which suggests their potential application as a cost-effective and secure medium for information encryption. Thus, our findings highlight the promising prospects of cation-π interactions in enhancing TS-FRET efficiency and advancing the field of organic photo-functional materials.
Plant bacterial diseases have inflicted substantial economic losses in global crop, fruit, and vegetable production. The conventional methods for managing these diseases typically rely on the application of antibiotics. However, these antibiotics often target the growth factors of the pathogenic bacteria, leading to the accumulation and emergence of drug-resistant strains, which exacerbates antibiotic resistance. Innovative methods are urgently needed to treat and prevent the toxicity caused by these pathogenic bacteria. Targeting virulence mechanisms in pathogens is a globally recognized and effective strategy for mitigating bacterial resistance. Type III secretion system (T3SS) serves as a crucial virulence determinant in Gram-negative pathogens, and its non-essentials for pathogen growth renders it an ideal target. Targeting the T3SS holds significant potential to alleviate selective pressure for resistance mutations in pathogens. Therefore, targeting T3SS in pathogenic bacteria, while preserving their growth, has emerged as a novel avenue for the development of antimicrobial drugs. In recent years, a multitude of small molecular inhibitors targeting T3SS have been identified. This article offers a comprehensive review of T3SS inhibitors in plant pathogens, while also presenting the latest research advancements in this research direction.
A novel Fe-doping three-dimensional flower-like Bi7O9I3 microspheres with plasmonic Bi and rich surface oxygen vacancies (Fe-Bi/Bi7O9I3/OVs) was prepared as catalysts, and further coupled with natural air diffusion electrode (NADE) to construct the heterogeneous visible-light-driven photoelectro-Fenton (HE-VL-PEF) process to enhance the degradation and mineralization of tetracycline (TC). Interfacial ≡Fe sites, OVs and Bi metal were simultaneously constructed via Fe doping, which effectively improved visible light absorption and the separation efficiency of photogenerated carriers to further accelerate the transformation of Fe(Ⅲ) to Fe(Ⅱ), achieving Fenton reaction recycling. HE-VL-PEF process could achieve enhanced treatment of pollutants, thanks to the synergistic effect of electro-Fenton (EF) and photo-Fenton (PF). NADE exhibited excellent H2O2 electrosynthesis without external oxygen-pumping equipment. Under the irradiation of visible light, Fe-Bi/Bi7O9I3/OVs could achieve more photoelectrons to accelerate the transformation of Fe(Ⅲ) to Fe(Ⅱ) or directly activate H2O2. DFT calculations also clearly demonstrated that except for the fast charge separation and transfer, Fe-Bi/Bi7O9I3/OVs could achieve a faster electron transport between Fe-O, facilitating Fe site acquire more electron. Consequently, the Fe-Bi/Bi7O9I3/OVs in HE-VL-PEF process presented performance superiorities including excellent pollutant removal (91.91%), low electric energy consumption of 66.34 kWh/kg total organic carbon (TOC), excellent reusability and wide pH adaptability (3–9).
An enantioselective catalytic method for the direct [4 + 1] annulation of yne–allylic acetates with pyrazolones has been realized by a copper-catalyzed remote strategy. A variety of enantioenriched spiropyrazolones are rapidly accessed in high yields with moderate to good enantiocontrol. The facile follow-up transformations highlight its potential utility in the synthesis of diverse spiropyrazolones building blocks.