Voltammetric Label‐free Detection of DNA Hypermethylation Using Polypyrrole‐modified Microelectrode Array

Abstract

An alternative strategy for the label‐free electrochemical detection of DNA hypermethylation using a microelectrode array as an oligodinucleotide (ODN) detector is presented. It relies on the oligonucleotide dependent electrostatic affinity interaction firstly with unmethylated ODN and then follow‐up with methylated DNA. The methylated cytosine status is quantified by monitoring the relative change in the exchange current at the ODN‐detector before and after the bisulfite treated DNA samples. This novel aproach displays unique advantages such as small working volumes of the analytes, low damage to DNA samples, easy integration of oligonucleides on the detector and signal evaluation.

Micro- and nano-devices for electrochemical sensing

“…The detection was carried out by differential pulse voltammetry (DPV) at clinically relevant concentrations (pg/mL) [ 67 ]. Other examples of micro- and nano-sized immunobiosensors have been reported for the detection of prostate-specific antigen (PSA) as a prostate carcinoma biomarker [ 26 ] and methylated DNA as a target for early tumor diagnosis and monitoring [ 68 ]. A microfluidic biosensor chip including Ag/AgCl and Au electrodes as RE and CE, respectively, and a Au nanoelectrodes array functionalized with a biosensor complex enabled the voltammetric determination of PSA with fM detection limit in nL volumes using a competitive immunoassay method [ 26 ].…”

An Overview of Biosensors Based on Glutathione Transferases and for the Detection of Glutathione

“…This biosensor presented specificity and reproducibility, with low detection limits, as well as being disposable and regenerable. More recently, a label‐free voltametric assay was also developed [75]. The biosensor used a 16‐channel platinum microelectrode array chip.…”

“…Indeed, under the prostatic carcinoma setting, GSTP1‐1 expression is silenced due to aberrant hypermethylation in its gene promoter. Different sensitive biosensors were developed and used for the determination of GSTP1‐1 hypermethylation as a prostate cancer biomarker [73–75].…”

“…The device was appropriate to detect methylation in GSTP1‐1 with good sensitivity and high specificity. Furthermore, it is suitable for a yes or no response in order to obtain a rapid diagnostic test [75]. A fluorogenic substrate that allows direct and selective detection of GSTP1‐1 activity in living cells was also developed [71].…”

Recent Advances in the Aptamer-Based Electrochemical Biosensors for Detecting Aflatoxin B1 and Its Pertinent Metabolite Aflatoxin M1

“…It is effectively used in the fields of environmental electrochemistry, organic chemistry, inorganic chemistry and biochemistry. The effectiveness of CV results from its capability of rapidly observing the redox behavior over a wide potential range [24,25].…”