Methylene blue covalently attached to single stranded DNA as electroactive label for potential bioassays

Abstract

a b s t r a c tMethylene blue is an electroactive molecule that has been employed for the detection of the DNA hybridization event in electrochemical sensors. However, its use as a covalent label is very scarce and in most of the cases, non-covalent interactions (hydrophobic, electrostatic) are employed. Although it has advantages as simplicity and fewer number of procedure steps, the covalent attachment is less exploited in the development of these sensors. In this article, the electrochemical behavior of methylene blue attached to different DNA-strands is studied. Several lengths (15-and 30-mer) and different degree of DNA modification (MB-DNA, MB-DNA-MB and MB-DNA-SH) have been studied. The highest signals were obtained for longer strands with two MB molecules. In all the cases the signal is enhanced by CNTnanostructuration of the electrode. Adsorption on these modified screen-printed electrodes allowed the amplification by employing an accumulation time. In this way, a sensitivity of −0.2864 A M −1 and a limit of detection of 800 nM for a 120 s accumulation time were obtained.

Prostate Cancer Biomarker Detection with Carbon Nanotubes Modified Screen Printed Electrodes

“…One of the remarkable advantages of the study is that DNA immobilization process does not require a covalent attachment step. These results constitute a relevant practical advance with respect to the behavior of the previously reported covalent attachment based DNA biosensors 33, 34. Furthermore, our detection strategy does not involve any time consuming electrode surface modifications and complex pretreatments.…”

Emerging materials for the electrochemical detection of COVID-19

“…(Cii) Ag ions, contained in the solution, are reduced into metallic silver (Ag) [62] . CVs of methylene blue covalently attached to a single-stranded DNA (Di) and methylene blue molecule (Dii) on bare (dotted line) and nanostructured screen-printed electrodes (solid line) [65] . (Ε) Comparison of CV response between the dsDNA (blue), dsDNA/rAzu (black), and PSD/rAzu (red).…”

The potential of electrochemistry for the detection of coronavirus-induced infections

“…The same group also employed methylene blue (MB) as the electroactive label for the detection of a SARS-CoV genome sequence [ 47 ], due to MB's high binding affinity to ssDNA and dsDNA and its reversible electrochemistry [ 48 ]. A limit of detection of 800 nM was achieved on a gold platform modified with carbon nanotubes (CNTs-AuSPE) as the transducer [ 47 ].…”