On-Demand Ligand-Base DNA Sensor with Electrochemical Impedance Spectroscopy

Abstract

We have developed a DNA sensor that can be finalized to detect a specific target on demand. The electrode surface was modified with 2,7-diamino-1,8-naphthyridine (DANP), a small molecule with nanomolar affinity for the cytosine bulge structure. The electrode was immersed in a solution of synthetic probe-DNA that had a cytosine bulge structure at one end and a complementary sequence to the target DNA at the other end. The strong binding between the cytosine bulge and DANP anchored the probe DNAs to the electrode surface, and the electrode became ready for target DNA sensing. The complementary sequence portion of the probe DNA can be changed as requested, allowing for the detection of a wide variety of targets. Electrochemical impedance spectroscopy (EIS) with the modified electrode detected target DNAs with a high sensitivity. The charge transfer resistance (Rct) extracted from EIS showed a logarithmic relationship with the concentration of target DNA. The limit of detection (LoD) was less than 0.01 μM. By this method, highly sensitive DNA sensors for various target sequences could be easily produced.

Exploiting epoxy-rich poly(ethylene glycol) films for highly selective ssDNA sensing via electrochemical impedance spectroscopy

“…This behavior is in contrast to some literature reports in which a logarithmic relationship with the concentration of target DNA was recorded. 14,15 This difference is probably related to the 3D character of our sensor in contrast to the 2D arrays designed in the above reports.…”

“…The respective detection limit of 0.1 μM is quite reasonable and comparable with literature data for other types of ssDNA sensors. 14,15 One can reasonably assume that this detection limit can be improved even further, e.g. by a larger loading of the PEG film with the probe ssDNA.…”

“…51–53 Consequently, for a better comparison, we used the same gold substrate for the PEG films and compared their efficiency with that of the direct ssDNA assembly, both in terms of immobilization of the probe ssDNA and the hybridization ability and selectivity of the resulting DNA sensing platform. As the suitable transduction technique, electrochemical tools were applied, with an emphasis put on electrochemical impedance spectroscopy, which, as expected, 11–16 turned out to be particular efficient for the given purpose.…”

“…4 The most popular techniques in this context are surface plasmon resonance (SPR), 6–8 fluorescence spectroscopy and microscopy, 5,9,10 and electrochemical tools. 11–16 Additional information about the ssDNA arrays and their hybridization efficiency is provided by X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, infrared spectroscopy, scanning tunneling microscopy, etc. 7,17–21…”

Enzyme-free electrochemical sensor platforms based on transition metal nanostructures for clinical diagnostics

“…Lactic acid biosensors are often developed based on lactate dehydrogenase (LDH) or oxidase (LOx) enzymes, which as sensors are more sophisticated and expensive. 57–59 In addition, the embedded enzymes or cofactors on the surface of the electrode is a challenging task and exhibits less durability. Numerous enzymes or mediator-free amperometric sensor platforms for sensing lactic acid were intensively developed to overcome the challenges with enzyme-based sensors.…”