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Nanochannel-Ionchannel Hybrid Device for Ultrasensitive Monitoring of Biomolecular Recognition Events
摘要： We propose an in-situ and label-free method for detection of biomolecular recognition event using nanochannel-ionchannel hybrid device integrated with an electrochemical detector. The aptamer is first immobilized on the outer surface of the nanochannel-ionchannel hybrid. Its binding with target thrombin in solution considerably regulates the mass transfer behavior of the device owing to the varied surface charge density and effective channel size. Using the electrochemical detector, the changed mass transport property can be in real-time monitored, which enables in-situ and label-free detection of thrombin-aptamer recognition. The solution pH has a significant influence on the detection sensitivity. Under optimal pH condition, the detection limit as low as 0.22 fM thrombin can be achieved, which is much lower than most reported work. The present nanofluidic device provides a simple, ultrasensitive and label-free platform for monitoring the biomolecular recognition events, which would hold great potential in exploring the biomolecules functions and reaction mechanism in the living systems.
关键词： nanofluidic,electrochemical detector,thrombin,nanochannel-ionchannel hybrid,biomolecular recognition
更新于2025-09-04 15:30:14
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Restriction of Molecular Rotors in Ultrathin Two-Dimensional Covalent Organic Framework Nanosheets for Sensing Signal Amplification
摘要： Covalent organic frameworks (COFs) have emerged as promising crystalline porous materials with well-defined structures, high porosity, tunable topology and functionalities suitable for various applications. However, studies of few-layered ultrathin two-dimensional (2D) COF nanosheets, which may lead to unprecedented properties and applications, are still limited. Herein we report the targeted synthesis of three azine-linked and imine-linked 2D COFs named NUS 30-32 using monomers containing aggregation-induced emission (AIE) rotor-active tetraphenylethylene (TPE) moieties, affording micro- and meso- dual pores in NUS-30 and NUS-32, and triple pores in NUS-31. For the first time, we demonstrate that these isostructural bulk COF powders can be exfoliated into ultrathin 2D nanosheets (2 – 4 nm thickness) by temperature-swing gas exfoliation approach. Compared with TPE monomers and COF model compounds, the AIE characteristic of NUS 30-32 nanosheets is distinctly suppressed due to the covalent restriction of the AIE molecular rotors in the confined 2D frameworks. As a result, the enhancement of conjugated conformations of NUS 30-32 nanosheets with unusual structure relaxation show signal amplification effect in biomolecular recognition of amino acids and small pharmaceutical molecules (L-dopa), exhibiting much higher sensitivity than their stacked bulk powders, TPE monomer, and COF model compound. Moreover, the binding affinity of the COF nanosheets toward amino acids can be controlled by increasing the number of azine moieties in the structure. Density functional theory (DFT) calculations reveal that binding affinity control results from the crucial geometric roles and stronger host-guest binding between azine moieties and amino acids. In addition, we demonstrate that minimal loading of the NUS-30 nanosheets in composite membranes can afford excellent performance for biomolecule detection. Our findings pave a way for the development of functional ultrathin 2D COF nanosheets with precise control over the nature, density, and arrangement of the binding active sites involved in enhanced molecule recognition.
关键词： molecular rotors,Covalent organic frameworks,aggregation-induced emission,biomolecular recognition,signal amplification,two-dimensional nanosheets
更新于2025-09-04 15:30:14