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71.
Wenqiang Lai Junyang Zhuang Juan Tang Guonan Chen Dianping Tang 《Mikrochimica acta》2012,178(3-4):357-365
We report on a new kind of electrochemical immunosensors for simultaneous determination of the biomarkers carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP). Thionine and ferrocene were applied as distinguishable electrochemical tags (and mediators) which were covalently conjugated on anti-AFP and anti-CEA antibodies, respectively, via carboxy groups. The resulting conjugates were co-immobilized on a glassy carbon electrode functionalized with gold nanoparticles. Finally, horseradish peroxidase (HRP) was immobilized onto the modified electrode. Labeled thionine and ferrocene, respectively, act as distinguishable tags for simultaneous determination of AFP and CEA due to the difference in the location of their voltammetric peaks. With a one-step immunoassay format, the analytes in the sample produced transparent immunoaffinity reaction with the corresponding antibodies on the electrode. Once the immunocomplex is formed, it partially inhibits the active center of the immobilized HRP, and this decreased the activity of HRP in terms of reduction of hydrogen peroxide. This immunosensor enables the simultaneous determination of AFP and CEA in a single run and within the same dynamic range (0.01–50?ng?mL?1) and the same lower detection limit (0.01?ng?mL?1). The reproducibility and stability of the immunosensors are acceptable. The dual immunosensor was applied to evaluate several specimens, and the assay results are in acceptable agreement with clinical data. Figure
This contribution devises a novel multiplexed electrochemical immunoassay for simultaneous detection of alpha-fetoprotein and carcinoembryonic antigen by using thionine and ferrocene as distinguishable signal tags on a one-spot immunosensor. The assay was performed by using one-step immunoreaction between the immobilized antibodies and the analytes. Although the linear range is relatively narrow, it completely meets the requirement of clinical diagnosis. 相似文献
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Sung-Gon Kim Kyung-Hyun Kim Junyang Jung Seung Koo Shin Kyo Han Ahn 《Journal of the American Chemical Society》2002,124(4):591-596
The enantiomeric recognition of alpha-chiral primary ammonium ions has been studied with benzene-based tripodal tris(oxazoline) receptors. Contrary to the literature and our expectation, a good level of chiral discrimination is observed with one of the tripodal receptors, which provides a C3-symmetric chiral environment on guest binding. The chiral discrimination has been found to be general in the case of alpha-aryl substituted guests, suggesting pi-pi interactions as an important factor. This result raises a question with respect to the origin of the chiral discrimination since little steric or electronic difference is expected between the diastereomeric inclusion complexes. Binding studies by NMR titration and isothermal titration calorimetry show that the chiral discrimination results from the different thermodynamic stabilities between the diastereomeric complexes and that the host-guest complex formation is driven by favorable enthalpy changes with a minor negative contribution by entropy changes. The X-ray crystal structures for both of the diastereomeric inclusion complexes are resolved, which unambiguously show the binding mode and provide clues on the origin of the chiral discrimination. Bond angle analyses indicate that the minor complex experiences a larger steric strain, which is discernible when it is viewed from "three-body" interactions between the host and the guest. The guest and oxazoline phenyl rings are well stacked, indicating interplay of the pi-pi interactions. The pi-pi interactions are believed to stabilize host-guest complexes, thereby endowing the highly flexible receptors with a substantial enantio-discrimination. 相似文献
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Xiaohui Li Qingqing Wu Jie Bai Songjun Hou Wenlin Jiang Chun Tang Hang Song Xiaojuan Huang Jueting Zheng Yang Yang Junyang Liu Yong Hu Jia Shi Zitong Liu Prof. Colin J. Lambert Deqing Zhang Prof. Wenjing Hong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(8):3306-3312
The experimental investigation of intermolecular charge transport in π-conjugated materials is challenging. Herein, we describe the investigation of charge transport through intermolecular and intramolecular paths in single-molecule and single-stacking thiophene junctions by the mechanically controllable break junction (MCBJ) technique. We found that the ability for intermolecular charge transport through different single-stacking junctions was approximately independent of the molecular structure, which contrasts with the strong length dependence of conductance in single-molecule junctions with the same building blocks, and the dominant charge-transport path of molecules with two anchors transited from an intramolecular to an intermolecular path when the degree of conjugation increased. An increase in conjugation further led to higher binding probability owing to the variation in binding energies, as supported by DFT calculations. 相似文献
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Hang Chen Yaorong Chen Hewei Zhang Wenqiang Cao Chao Fang Yicheng Zhou Zongyuan Xiao Jia Shi Wenbo Chen Junyang Liu Wenjing Hong 《中国化学快报》2022,33(1):523-526
Quantum interference(QI) effects, which offer unique opportunities to widely manipulate the charge transport properties in the molecular junctions, will have the potential for achieving high thermopower.Here we developed a scanning tunneling microscope break junction technique to investigate the thermopower through single-molecule thiophene junctions. We observed that the thermopower of 2,4-TPSAc with destructive quantum interference(DQI) was nearly twice of 2,5-TP-SAc without DQI, while the con... 相似文献
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Dr. Fengqin Li Junru Li Weiqiang Yang Dr. Shuai Yang Congshuo Chen Ling Du Junyang Mei Dr. Qianyun Tang Xiaojing Chen Dr. Chi Yao Prof. Dayong Yang Prof. Xiaolei Zuo Prof. Peifeng Liu 《Angewandte Chemie (International ed. in English)》2023,62(32):e202305536
The trans-cleavage property of CRISPR-Cas12a system makes it an excellent tool for disease diagnosis. Nevertheless, most methods based on CRISPR-Cas system still require pre-amplification of the target to achieve the desired detection sensitivity. Here we generate Framework-Hotspot reporters (FHRs) with different local densities to investigate their effect on trans-cleavage activity of Cas12a. We find that the cleavage efficiency increases and the cleavage rate accelerates with increasing reporter density. We further construct a modular sensing platform with CRISPR-Cas12a-based target recognition and FHR-based signal transduction. Encouragingly, this modular platform enables sensitive (100 fM) and rapid (<15 min) detection of pathogen nucleic acids without pre-amplification, as well as detection of tumor protein markers in clinical samples. The design provides a facile strategy for enhanced trans cleavage of Cas12a, which accelerates and broadens its applications in biosensing. 相似文献
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Junyang Sui Ruiyang Dong Siyuan Liao Zeyuan Zhao Yubo Wang Hai-Feng Zhang 《Annalen der Physik》2023,535(3):2200509
In this paper, a Janus metastructure (JMS) is proposed that can act both as a logic gate and detect multiple physical quantities. By adjusting the incident angle of electromagnetic waves, arranging the dielectrics asymmetrically, and using the anisotropy of the plasma, the Janus function can be obtained, which gives the metastructure a multiscale property. Sharp transmission peak (TP) is generated by located defect mode resonance. The AND logic gate on the positive and negative scales can be realized by judging the TP value. By locking the point frequency of the TP, the refractive index, magnetic field strength, incident angle, and plasma density can be detected simultaneously on the two scales in the GHz range, which is rarely studied. Good sensing performances are also owned, and the corresponding optimal sensitivities are 0.095 (2πc/d)/RIU, 9.42 × 10−3 (2πc/d)/T, 1.48 × 10−3 (2πc/d)/°, and 0.035 (2πc/d) m3/1019, respectively. Compared with the traditional sensors, the proposed JMS equipped with two scales not only can realize the logic gate but also measure multiple physical quantities, which has a certain application potential. 相似文献