A simple, sensitive and label-free electrochemical sensor is developed for detection of Hg(2+) based on the strong and stable T-Hg(2+)-T mismatches. In the presence of Mg(2+), the parallel G-quadruplex structures could be specifically recognized and precipitated in parallel conformation. Therefore, the guanine nanowire was generated on the electrode surface, triggering the electrochemical H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). In this research, a new method of signal amplification for the quantitative detection of Hg(2+) was described based on the direct growth of guanine nanowire via guanine nanowire. Under optimum conditions, Hg(2+) was detected in the range of 100 pM-100 nM, and the detection limit is 33 pM. Compared to the traditional single G-quadruplex label unit, this electrochemical sensor showed high sensitivity and selectivity for detecting Hg(2+).
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http://dx.doi.org/10.1016/j.jhazmat.2016.01.048 | DOI Listing |
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November 2024
Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA.
Structural DNA nanotechnology enables the self-organization of matter at the nanometer scale, but approaches to expand the inorganic and electrical functionality of these scaffolds remain limited. Developments in nucleic acid metallics have enabled the incorporation of site-specific metal ions in DNA duplexes and provide a means of functionalizing the double helix with atomistic precision. Here a class of 2D DNA nanostructures that incorporate the cytosine-Ag-cytosine (dC:Ag:dC) base pair as a chemical trigger for self-assembly is described.
View Article and Find Full Text PDFNanoscale
October 2024
National Key Laboratory of Biobased Transportation Fuel Technology, Zhejiang University-University of Illinois, Urbana-Champaign Institute, Zhejiang University, Haining, 314400, P.R. China.
The G-quadruplex (GQ) formed by guanine-rich DNA strands exhibits superior thermal stability and electric properties, which have generated substantial interest in applying GQ DNA to bioelectric interfaces. However, single G-wires formed by GQs have not yet surpassed the μm length due to the lack of an optimal assembly protocol and understanding of assembly mechanisms that limit application. Herein, we optimized a self-assembly protocol for a short 4-nt oligonucleotide (dG4) to achieve micrometer lengths of G-wires, including the buffer composition, incubation process and surface assembly.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2022
Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA.
The G-quadruplex is a fascinating nucleic acid motif with implications in biology, medicine, and nanotechnologies. G-quadruplexes can form in the telomeres at the edges of chromosomes and in other guanine-rich regions of the genome. They can also be engineered for exploitation as biological materials for nanodevices.
View Article and Find Full Text PDFAnal Chem
April 2022
Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, People's Republic of China.
Although the CRISPR/Cas system has pioneered a new generation of analytical techniques, there remain many challenges in developing a label-free, accurate, and reliable CRISPR/Cas-based assay for reporting the levels of low abundance biomolecules in complex biological samples. Here, we reported a novel CRISPR-derived resonance Rayleigh scattering (RRS) amplification strategy and logical circuit based on a guanine nanowire (G-wire) assisted non-cross-linking hybridization chain reaction (GWancHCR) for label-free detection of lipopolysaccharide (LPS). In the presence of a target, the protospacer-adjacent motif-inserted aptamer is rationally designed to specifically combine with LPS rather than Cas12a, suppressing the trans-cleavage activity of CRISPR/Cas12a and retaining the reporter probes to trigger non-cross-linking aggregation.
View Article and Find Full Text PDFMicromachines (Basel)
March 2021
Institute of Translational Pharmacology, National Research Council, IFT-CNR, 00133 Rome, Italy.
This article demonstrates the possibility to use a novel powerful approach based on Raman mapping of analyte solutions drop casted on a disordered array of Ag covered silicon nanowires (Ag/SiNWs), to identify the characteristic spectral signal of the four DNA bases, adenine (A), thymine (T), cytosine (C), and guanine (G), at concentration as low as 10 ng/µL, and to study their specific way of interacting with the nanostructured substrate. The results show a distinctive and amplified interaction of guanine, the base that is most susceptible to oxidation, with the nanostructured surface. Our findings explain the recently revealed diverse behaviour of cancer and normal DNA deposited on the same Ag/SiNWs, which is ascribed to mechanical deformation and base lesions present on the oxidised DNA molecule backbone and causes detectable variation in the Raman signal, usable for diagnostic purposes.
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