An electrochemical molecular switch for one-step, reusable detection of a single-base mutation of DNA

Abstract

A new strategy for one-step, reusable and sensitive detection of a single-base mutation based on an electrochemical molecular switch is developed in the present work. When the hybridization reaction takes place in the presence of target DNA, the Fc-labeled terminal of the open switch molecule can be captured by the probe through the predesigned complementary bases of both sequences. By this method, a signal-on sensor featuring both generalizability and simplicity towards reagentless detection of DNA with sensitivity and selectivity electrochemical system is built on. The approach had been demonstrated with the identification of a single-base mutation of alpha-thalassemia point mutation in Hb Constant Spring codon 142 (TAA --> CAA). The wild-type and mutant-type of the synthetic 16 mer DNA sequences as the model targets were successfully discriminated. The results showed that the response signal was linear to the logarithm of the target concentration in the range from 0.01 to 100 pM with a detection limit of 0.01 pM. The regeneration experiment demonstrated that the sensor interface can be easily and successfully regenerated. All these revealed that the present system is a promising candidate for single-base mutation discrimination.

Effect of diluent chain length on the performance of the electrochemical DNA sensor at elevated temperature

“…5 Owing to the low electroactive background typically observed in clinical samples, and the promising response speed, cost and convenience of microelectronics, 6,7 electrochemical methods for DNA detection have attracted increasing attention in recent years. [8][9][10][11][12][13] At least a dozen electrochemical DNA sensing approaches have been developed to date, specifically; the Plaxco group and others have developed a label-free, reusable, near realtime electrochemical DNA (E-DNA) sensing platform. [14][15][16][17] As an electrochemical equivalent of the optical ''molecular beacon'' detection system, the E-DNA sensor is comprised of a redoxlabeled stem-loop or linear DNA probe covalently attached to an interrogating electrode.…”

Using the synergism strategy of multi-redox-modified signaling probe, background suppression and large surface area electrode for highly sensitive and specific electrochemical sensing of specific DNA sequence

“…The detection limit was confirmed to be ∼2 fM (S/N = 3). This detection limit is much lower than that obtained from the most part of "signal-on" E-DNA sensors reported without using above-mentioned amplification methods [16][17][18][19][20]. Such high sensitivity can be ascribed to the synergism of three aspects, multi-redox labels, background suppression and large surface area Au electrode.…”

“…However, such class of methods suffer from several drawbacks including complex handling procedures, not robust enough for detection, weak working capability and vulnerability to contamination in complex matrixes. In order to circumvent these shortcomings, several E-DNA sensors without using abovementioned amplification methods have since been developed [16][17][18][19]. Though most of drawbacks have been alleviated to some extent, the problem of weak working capability in real complex samples still exists.…”

A highly sensitive and specific electrochemical sensing method for robust detection of Escherichia coli lac Z gene sequence

“…After hybridization, when interrogated with ACV at 20 Hz, we observed a large increase in MB current ( $ 0.21 μA). For this class of sensors, the change in the distance between the indicator of probe and the electrode surface often parallels the change in the rate of electron transport and the resultant redox current (Jin et al, 2010;Xiao et al, 2005Xiao et al, , 2006. In this case, the increase in the MB current can be attributed to the formation of 13-base DNA duplex between the target DNA and the SP.…”