Enhanced Charge Transfer by Gold Nanoparticle at DNA Modified Electrode and Its Application to Label-Free DNA Detection

Abstract

Rational utilization of nanomaterials to construct electrochemical nucleic acid sensors has attracted large attention in recent years. In this work, we systematically interrogate the interaction between gold nanoparticles (GNPs) and single-strand DNA (ssDNA) immobilized on an electrode surface and then take advantage of the ultrahigh charge-transfer efficiency of GNPs to develop a novel DNA sensing method. Specifically, ssDNA modified gold electrode can adsorb GNPs because of the interaction between gold and nitrogen-containing bases; thus, the negative electrochemical species [Fe(CN)6](3-/4-) may transfer electrons to electrode through adsorbed GNPs. In the presence of target DNA, the formed double-strand DNA (dsDNA) cannot capture GNPs onto the electrode surface and the dsDNA may result in a large charge-transfer resistance owing to the negatively charged phosphate backbones of DNA. So a simple but sensitive method for the detection of target DNA can be developed by using GNPs without any requirement of modification. Experimental results demonstrate that the electrochemical method we have proposed in this work can detect as low as 1 pM breast cancer gene BRCA1 in a 10 μL sample volume without any signal amplification process or the involvement of other synthesized complex, which may provide an alternative for cancer DNA detection. This method may also be generalized for detecting a spectrum of targets using functional DNA (aptamer, metal-specific oligonucleotide, or DNAzyme) in the future.

Gold nanoparticles-based electrochemical method for the detection of protein kinase with a peptide-like inhibitor as the bioreceptor

“…The decrease in curves c and d can be explained by the fact that AuNPs assembled onto the electrode surface facilitate the electron transfer of ferricyanide. 66,67 When the electrode was incubated with PKA (curve e), a slight increase in R et was observed. This indicated that the formation of IP 20 -PKA complexes on the sensor surface caused a barrier for the electron transfer of ferricyanide.…”

“…The unique electrical properties of AuNPs may lead to a significant decrease in the charge transfer resistance. 66,67 When the Fc-peptide was used in this design, the network of AuNPs/ Fc-peptide on the electrode surface would exhibit an amplified voltammetric signal from the electrochemical oxidation of Fc tags. However, when the electrode was covered with PKA, IP 20 immobilized on the electrode surface would lose its ability to trigger the formation of AuNPs-based network architecture due to the formation of IP 20 -PKA complex.…”

“…However, when the peptide immobilized on the electrode surface bound with PKA, the resulting peptide-PKA complex prevented the assembly of AuNPs as the principle in the colorimetric assay. As AuNPs show excellent electrical conductivity and high surface area of AuNPs, [63][64][65][66][67] this process could easily be monitored by electrochemical impedance spectroscopy or voltammetric technique by employing a redox-labeled PKA-binding peptide. The proposed electrochemical method not only features simple manipulation principle similar to that of colorimetric assay but also shows high sensitivity and specificity of electroanalysis.…”

Sensitive colorimetric assays for α-glucosidase activity and inhibitor screening based on unmodified gold nanoparticles

“…The AuNPs based colorimetric methods are usually developed based on enzyme-mimic activities, interparticle cross-linking or a destabilization induced aggregation mechanism. Our group has also proposed series of AuNPs based biosensor for detection of DNA [21][22][23], metal ions [24,25], proteins [26,27], bioactive molecules [28,29] and cancer markers [30,31].…”

An electrochemical biosensor for DNA detection based on tungsten disulfide/multi-walled carbon nanotube composites and hybridization chain reaction amplification

“…Sequence-specific detection of DNA has been reported for playing an important role in the precaution of genetic or pathogenic diseases, treatment of viral and bacterial infections, and prognosis of cancer [1,2]. Therefore, ultrasensitive and selective detection of DNA has attracted particular attention [3].…”