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Journal ArticleDOI: 10.1021/ACS.ANALCHEM.0C05055

Stochastic Collision Electrochemistry from Single G-Quadruplex/Hemin: Electrochemical Amplification and MicroRNA Sensing.

04 Mar 2021-Analytical Chemistry (American Chemical Society (ACS))-Vol. 93, Iss: 10, pp 4593-4600
Abstract: Stochastic collision electrochemistry is a hot topic in single molecule/particle research, which provides an opportunity to investigate the details of the single molecule/particle reaction mechanism that is always masked in ensemble-averaged measurements. In this work, we develop an electrochemical amplification strategy to monitor the electrocatalytic behavior of single G-quadruplex/hemin (GQH) for the reaction between hydrogen peroxide and hydroquinone (HQ) through the collision upon a gold nanoelectrode. The intrinsic peroxidase activities of single GQH were investigated by stochastic collision electrochemical measurements, giving further insights into understanding biocatalytic processes. Based on the unique catalytic activity of GQH, we have also designed a hybridization chain reaction strategy to detect miRNA-15 with good selectivity and sensitivity. This work provided a meaningful strategy to investigate the electrochemical amplification and the broad application for nucleic acid sensing at the single molecule/particle level.

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8 results found

Journal ArticleDOI: 10.1021/ACSAMI.1C09000
Hua Chai1, Wenbo Cheng1, Dayong Jin2, Dayong Jin3  +1 moreInstitutions (3)
Abstract: With the continuous development of DNA nanotechnology, various spatial DNA structures and assembly techniques emerge. Hybridization chain reaction (HCR) is a typical example with exciting features and bright prospects in biosensing, which has been intensively investigated in the past decade. In this Spotlight on Applications, we summarize the assembly principles of conventional HCR and some novel forms of linear/nonlinear HCR. With advantages like great assembly kinetics, facile operation, and an enzyme-free and isothermal reaction, these strategies can be integrated with most mainstream reporters (e.g., fluorescence, electrochemistry, and colorimetry) for the ultrasensitive detection of abundant targets. Particularly, we select several representative studies to better illustrate the novel ideas and performances of HCR strategies. Theoretical and practical utilities are confirmed for a range of biosensing applications. In the end, a deep discussion is provided about the challenges and future tasks of this field.

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3 Citations

Journal ArticleDOI: 10.1021/ACS.JPCLETT.1C01389
Haoran Tang1, Hao Wang1, Jiahao Du1, Dandan Zhao1  +2 moreInstitutions (1)
Abstract: Enzymes encapsulated in metal-organic frameworks (enzyme@MOFs), as a promising immobilized enzyme, were investigated for intrinsic catalytic activities at the single entity level via a stochastic collision electrochemical technique. Zeolitic imidazolate frameworks with amorphous (aZIF-8) and crystalline (ZIF-8) structures were chosen as model MOFs to encapsulate glucose oxidase (GOx). We carried out single enzyme@MOF nanoparticle (NP) collision experiments using the carbon ultramicroelectrode (CUME), which demonstrated that the catalytic activity of GOx@ZIF-8 NPs was much less than GOx@aZIF-8 NPs. Meanwhile, the kcat and TON per GOx in aZIF-8 NPs were obtained, revealing the intrinsic catalytic activity of GOx in aZIF-8 NPs at the single entity level. This strategy is the first approach for investigating enzyme@MOFs at a single entity level, which can not only broaden the horizons of single entity electrochemistry (SEE) but also provide further insights into research on electrochemistry, catalysis, and nanocomposites.

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1 Citations

Journal ArticleDOI: 10.1039/D1AN01603B
Huang Xiaodong1, He Zhenni1, Kejie Zhou1, Huizhen Zhi1  +1 moreInstitutions (1)
28 Oct 2021-Analyst
Abstract: G-quadruplex-based complexes have been widely used in various analytical methods due to their outstanding capabilities of generating colorimetric, fluorescent or electrochemical signals. However, since loop sequences in traditional G-quadruplex structures are quite short, it is difficult to establish biosensors solely using G-quadruplex-based complexes. Herein, we attempted to lengthen the loop sequences of G-quadruplex structures and found that G-quadruplex-hemin DNAzymes (G-DNAzymes) with long loops (even 30 nucleotides) maintain high peroxidase activity. In addition, the peroxidase activity is not affected by the hybridization of the long loop with its complementary counterpart. Consequently, G-DNAzyme can be endowed with an additional function by taking the long loop as a recognition element, which may facilitate the construction of diverse colorimetric biosensors. Furthermore, by designing an apurinic/apyrimidinic site or a complementary sequence of microRNA-21 (miRNA-21) in long loops, bifunctional G-DNAzymes can be split in the presence of apurinic/apyrimidinic endonuclease 1 (APE1) or miRNA-21, decreasing their peroxidase activities. Accordingly, APE1 and miRNA-21 are quantified using 3,3',5,5'-tetramethylbenzidine as a chromophore. Using the G-DNAzyme, APE1 can be detected in a linear range from 2.5 to 22.5 U mL-1 with a LOD of 1.8 U mL-1. It is to be noted that benefitting from duplex-specific nuclease-induced signal amplification, the linear range of the miRNA-21 biosensor is broadened to 5 orders of magnitude, while the limit of detection is as low as 73 fM. This work demonstrates that G-DNAzymes with long loops can both generate signals and recognize targets, providing an alternative strategy to design G-quadruplex-based analytical methods.

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Topics: AP site (51%)

Open accessJournal ArticleDOI: 10.1016/J.BIOS.2021.113806
Hanmei Deng1, Ming-Jun Xiao1, Yaqin Chai1, Ruo Yuan1  +1 moreInstitutions (1)
Abstract: Photocathodic biosensor has great capability in anti-interference from reductive substances, however, the low signal intensity of photoactive species with inferior detection sensitivity restricts its wide application. In this work, the P3HT-PbS nanocomposites were synthesized as signal tags, by integrating with target-trigger generated hemin/G-quadruplex nanotail as bi-enhancer to significantly apmplify the photocurrent, an ultrasensitive photocathodic biosensor was proposed for detection of β2-microglobulin (β2-MG). Impressively, P3HT with cathode signal is an attractive polymer consisted of substantial thiophene groups with high absorption coefficient and mobility of photo-generated holes, which could anchor with the PbS dots as sensitizer, providing a high charge mobility and strong photosensitivity. More importantly, target-trigger generated hemin/G-quadruplexes could accept the electron from illuminated photoactive species through the conversion of Fe(III)/Fe(II) in hemin, effectively reducing charge recombination rate as well as accelerating the generation of electron acceptor O2 in the assistant of H2O2. Moreover, hemin/G-quadruplexes inherited the HRP mimicking catalytic capability that further improved the produce of plentiful O2. As a result, PEC cathode signal was significantly enhanced for sensitive analysis of β2-MG protein with a good detection range of 0.1 pg/mL to 100 ng/mL. It would provide a path for establishing PEC platform with excellent anti-interference ability and extend the application of photoelectrochemical (PEC) biosensor in bioanalysis and early disease diagnosis.

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Topics: Biosensor (52%)


57 results found

Journal ArticleDOI: 10.1038/35020524
10 Aug 2000-Nature
Abstract: Molecular recognition between complementary strands of DNA allows construction on a nanometre length scale. For example, DNA tags may be used to organize the assembly of colloidal particles, and DNA templates can direct the growth of semiconductor nanocrystals and metal wires. As a structural material in its own right, DNA can be used to make ordered static arrays of tiles, linked rings and polyhedra. The construction of active devices is also possible--for example, a nanomechanical switch, whose conformation is changed by inducing a transition in the chirality of the DNA double helix. Melting of chemically modified DNA has been induced by optical absorption, and conformational changes caused by the binding of oligonucleotides or other small groups have been shown to change the enzymatic activity of ribozymes. Here we report the construction of a DNA machine in which the DNA is used not only as a structural material, but also as 'fuel'. The machine, made from three strands of DNA, has the form of a pair of tweezers. It may be closed and opened by addition of auxiliary strands of 'fuel' DNA; each cycle produces a duplex DNA waste product.

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Topics: DNA machine (70%), DNA origami (64%), Molecular models of DNA (63%) ... read more

1,917 Citations

Open accessJournal ArticleDOI: 10.1073/PNAS.0407024101
Robert M. Dirks1, Niles A. PierceInstitutions (1)
Abstract: We introduce the concept of hybridization chain reaction (HCR), in which stable DNA monomers assemble only upon exposure to a target DNA fragment. In the simplest version of this process, two stable species of DNA hairpins coexist in solution until the introduction of initiator strands triggers a cascade of hybridization events that yields nicked double helices analogous to alternating copolymers. The average molecular weight of the HCR products varies inversely with initiator concentration. Amplification of more diverse recognition events can be achieved by coupling HCR to aptamer triggers. This functionality allows DNA to act as an amplifying transducer for biosensing applications.

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1,308 Citations

Open accessJournal ArticleDOI: 10.1074/JBC.M204571200
Abstract: Laccase is a polyphenol oxidase, which belongs to the family of blue multicopper oxidases. These enzymes catalyze the one-electron oxidation of four reducing-substrate molecules concomitant with the four-electron reduction of molecular oxygen to water. Laccases oxidize a broad range of substrates, preferably phenolic compounds. In the presence of mediators, fungal laccases exhibit an enlarged substrate range and are then able to oxidize compounds with a redox potential exceeding their own. Until now, only one crystal structure of a laccase in an inactive, type-2 copper-depleted form has been reported. We present here the first crystal structure of an active laccase containing a full complement of coppers, the complete polypeptide chain together with seven carbohydrate moieties. Despite the presence of all coppers in the new structure, the folds of the two laccases are quite similar. The coordination of the type-3 coppers, however, is distinctly different. The geometry of the trinuclear copper cluster in the Trametes versicolor laccase is similar to that found in the ascorbate oxidase and that of mammalian ceruloplasmin structures, suggesting a common reaction mechanism for the copper oxidation and the O2 reduction. In contrast to most blue copper proteins, the type-1 copper in the T. versicolorlaccase has no axial ligand and is only 3-fold coordinated. Previously, a modest elevation of the redox potential was attributed to the lack of an axial ligand. Based on the present structural data and sequence comparisons, a mechanism is presented to explain how laccases could tune their redox potential by as much as 200 mV.

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Topics: Laccase (61%), Multicopper oxidase (57%), Copper protein (54%) ... read more

757 Citations

Journal ArticleDOI: 10.1016/0041-008X(92)90273-U
Topics: Quinone (51%)

674 Citations

Journal ArticleDOI: 10.1021/JA072344W
Xiaoyin Xiao1, Allen J. Bard1Institutions (1)
Abstract: The collisions of single platinum nanoparticles at an ultramicroelectrode were observed electrochemically by their characteristic current−time transients for a particle-catalyzed reaction. A single event is characterized by the current generated by an electrocatalyzed reaction of an indicator species (proton, hydrogen peroxide) present in solution. Since the indicator reaction does not occur at the selected ultramicroelectrode and can involve a high concentration of indicator species with a much larger diffusion coefficient than the nanoparticle, large amplification (10 orders of magnitude or more) in the current occurs. Every collision produces a unique current−time profile that can be correlated with the particle size, the particle residence time, and the nature of the particle interaction with the electrode surface. Applications to studying heterogeneous kinetics at single nanoparticles, determining particle size distributions, and as a very sensitive electroanalytical technique are suggested.

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Topics: Ultramicroelectrode (59%)

510 Citations