A surface redox reaction of a strongly adsorbed redox couple involving interactions between the adsorbed particles was analyzed theoretically under conditions of square-wave voltammetry (SWV). If uniform interactions act between the adsorbed particles, the effect of interaction forces is represented through the product of the relative surface coverage and Frumkin interaction parameter a. The ki...

An electronic nanoswitch is described based on the conformational change of the DNA sequence in the presence of stabilizing ligands. The new electrochemical biosensor was prepared by modifying a screen-printed graphite electrode (SPE) with functionalized SiO2 nanoparticles [(SiO2-N-propylpiperazine-N-(2-mercaptopropane-1-one) (SiO2@NPPNSH)] and Au nanoparticles (AuNPs). These nanoparticles are ...

In this paper, we describe the development of an electrochemical DNA aptamer-based biosensor for detection of interferon (IFN)-γ. A DNA hairpin containing IFN-γ-binding aptamer was thiolated, conjugated with methylene blue (MB) redox tag, and immobilized on a gold electrode by self-assembly. Binding of IFN-γ caused the aptamer hairpin to unfold, pushing MB redox molecules away from the electrod...

Circulating tumor DNA (ctDNA), which includes DNA mutations, epigenetic alterations and other forms of tumor-specific abnormalities, is a promising "real-time" biomarker for noninvasive cancer assessment. Tumor DNA is of great value in the process of cancer treatment, including diagnostic and prognostic information before, during treatment and at progression. Here we introduce a peptide nucleic...

conclusions this easily fabricated electrode together with the fast and sensitive sw voltammetry was successfully applied for the determination of concentration of atz at trace levels, in different water samples. results the results revealed that decrease in peak current was proportional to atz concentration over the range of 5-75 ng/ml. the limit of detection (lod) and limit of quantification ...

5-fluorouracil is a widely used anticancer drug with many side effects on humans, and hence its analysis in biological samples is very important. Accordingly, a novel sensitive electrochemical approach was fabricated by incorporating graphene quantum dots (GCD) and 1-butylpyridinium bromide (BPBr) in the formulation of a carbon paste electrode (GQD/BPBr/CPE). The GQD was synthesized and charact...

Oriented for the rapid diagnosis of HIV infection, highly sensitive and facile electrochemical assays for HIV-1 reverse transcriptase (HIV1-RT) are presented in this article. A non-labeled and a labeled assay format were based on the formation of self-assembled monolayers (SAMs) of either lipoic acid active ester or a newly synthesized ferrocene (Fc)-labeled cystamine derivative on electrode su...

Electrostatic redox probes interaction has been widely rendered for DNA quantification. We have established a proof-of-principle by using the ruthenium hexaamine molecule [Ru(NH(3))(6)](3+). We have applied this method for real-time electrochemical monitoring of a loop mediated isothermal amplification (LAMP) amplicon of target genes of Escherichia coli and Staphylococcus aureus by square wave ...

This paper reports the use of polished silver solid amalgam electrode (p-AgSAE) allied to square wave voltammetry (SWV) in development a simple, sensitive, fast and green electroanalytical methodology for trifluralin herbicide determination fresh food samples. The experimental (supporting electrolyte potential time accumulation) voltammetric (pulse frequency, pulse amplitude scan increment pote...