Abstract
Guanine-rich nucleic acids are able to self-assemble into G-quadruplex four-stranded secondary structures, which are found at the level of telomeric regions of chromosomes, oncogene promoter sequences and other biologically-relevant regions of the genome. Due to their extraordinary stiffness and biological role, G-quadruples become relevant in areas ranging from structural biology to medicinal chemistry, supra-molecular chemistry, nanotechnology and biosensor technology. In addition to classical methodologies, such as circular dichroism, nuclear magnetic resonance or crystallography, electrochemical methods have been successfully used for the rapid detection of the conformational changes from single-strand to G-quadruplex. This review presents recent advances on the G-quadruplex electrochemical characterization and on the design and applications of G-quadruplex electrochemical biosensors, with special emphasis on the G-quadruplex aptasensors and hemin/G-quadruplex peroxidase-mimicking DNAzyme biosensors.
Highlights
DNA sequences rich in guanine (G) bases are able to self-assemble into four-stranded secondary structures called G-quadruplexes (G4 or GQ), (Scheme 1)
G4 taking into account the thrombin interaction with thrombin binding aptamers (TBA) primary and secondary structures, as well strands coiled around thrombin, leading to the formation of a robust TBA-thrombin complex that as the thrombin folding in the presence of alkaline metals [32,38]
Using a more complex design, based on conductive graphene-3,4,9,10-perylenetetracarboxylic dianhydride nanocomposites as a sensor platform and PtCo nanochains–thionine–Pt–horseradish peroxidase-labelled secondary TBA for signal amplification, thrombin was detected at a linear range from 10 ́15 –10 ́9 M and a 6.5 ˆ 10 ́16 M detection limit [60]
Summary
DNA sequences rich in guanine (G) bases are able to self-assemble into four-stranded secondary structures called G-quadruplexes (G4 or GQ), (Scheme 1). G4 formation has been associated with a number of diseases, such as cancer, HIV and diabetes [3,5] Due to their extraordinary stiffness and biological role, G4s become relevant in areas ranging from structural biology to medicinal chemistry, supra-molecular chemistry, nanotechnology and biosensor technology. G-rich oligonucleotides (ODNs) are able to telomere dysfunction in cancer cells [2,15,16]. The electrochemical research resonance, crystallography or atomic force microscopy (AFM) [20,21,22,23]. G4 electrochemical biosensors that use labels amplification strategies, design and applications of the.
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