Gold nanoparticles deposited on fluorine-doped tin oxide surface as an effective platform for fabricating a highly sensitive and specific digoxin aptasensor

Abstract

In this paper we used a modified fluorine-doped tin oxide (FTO) as the substrate of a novel aptasensor for electrochemical determination of digoxin. For this purpose, a selective thiolated digoxin aptamer was immobilized onto the gold nanoparticles deposited FTO (GNPs/FTO) surface. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used for the characterization of modified surfaces. The aptasensor response was based on decrease in the methylene blue (MB) current, as an electrochemical probe, after incubating with digoxin. Digoxin can be determined in linear concentration range from 0.02 to 0.2 µg/L by differential pulse voltammetry (DPV). The detection limit of the proposed aptasensor was 0.01 µg/L. Also, the fabricated aptasensor was applied to determine digoxin in urine and blood plasma samples with satisfactory results. Furthermore, high sensitivity and specificity, low detection limit and fast response, can make it possible to determine trace amounts of digoxin for routine clinical analysis.

3-Mercapto propionic acid self-assembled on gold nano-particles applied for modification of screen-printed electrode as a new digoxin electrochemical aptasensor using graphene oxide-based signal-on strategy

“…The calibration plot demonstrated a good linear relationship between the monitored signal and the logarithm of digoxin concentration over the range of 0.1 pM to 1 µM with a detection limit of 0.05 pM. Table 1 shows a comparison between characteristics of the different digoxin aptasensors [18,38,39]. As seen, the proposed aptasensor delivered much better limit of detection, also a wide linear dynamic range.…”

A new electrochemical sensor based on carbon paste electrode/Ru(III) complex for determination of nitrite: Electrochemical impedance and cyclic voltammetry measurements

“…The LOD, determined using CPE/Ru(III)-BSAP-PLA electrode (1.39 ×10 -6 mol L -1 ), is lower than that evaluated with modified cavity microelectrode (LOD=1.81×10 -6 mol L -1 ; Sensitivity=5.80×10 -3 A (mol L -1 ) -1 ) [46].…”

“…These studies include the determination of heavy metals using modified potentiometric carbon paste electrode based on a novel nano-sensing layer, ionic liquid/graphene modified electrode and potentiometric sensor based on derivative carbon materials [41][42][43]. Other studies have also developed analysis of drugs and biomolecules using electrochemical sensor based on magnetic multi-walled carbon nanotubes, Co 3 O 4 -reduced graphene oxide modified carbon paste electrode, modified fluorine-doped tin oxide (FTO) aptasensor, Fe 3 O 4 nanoparticle-decorated reduced graphene oxide modified electrode and high performance magnetite/carbon nanotubes paste electrode [44][45][46][47][48].…”

Optical Biosensors for Therapeutic Drug Monitoring

“…Amperometric biosensors measure current flows generated by an electrochemical reaction at a constant potential, where the current intensity is directly related to the concentration of the substance oxidized and reduced on the electrode's surface [63]. These types of biosensors have been used in quantifying aminoglycoside antibiotics [66], bronchodilators (such as theophylline) [67], anti-arrhythmic [68], and anticancer drugs [69][70][71][72][73][74][75][76][77][78][79][80][81][82][83].…”