Fractal gold modified electrode for ultrasensitive thrombin detection

Abstract

We report a label-free and ultrasensitive aptasensor based on a fractal gold modified (FracAu) electrode for thrombin detection with a femtomolar detection limit. The FracAu electrode was prepared by electrodeposition of hydrogen tetrachloroaurate (HAuCl(4)) onto a bare indium tin oxide (ITO) electrode surface. After this process the electrode was characterized by SEM. A thiol-modified aptamer against thrombin was immobilized on the FracAu electrode through a self-assembling process. Upon thrombin binding, the interfacial electron transfer of the FracAu electrode was perturbed by the formation of an aptamer-thrombin complex. The concentration of thrombin in the sample solution was determined by measuring the change in the oxidation peak current of hydroxymethyl ferrocene (C(11)H(12)FeO) with differential pulse voltammetry (DPV). The current response (reduced peak current) had a linear relationship with the logarithm of thrombin concentrations in the range of 10(-15) to 10(-10) M with a detection limit of 5.7 fM. Furthermore, the as-prepared FracAu electrode exhibited high selectivity. The application of FracAu electrodes may be extended to prepare other types of biosensors, such as immunosensors, enzyme biosensors and DNA biosensors. These results show that FracAu electrodes have great promise for clinical diagnosis of disease-related biomarkers.

An aptamer-based single particle method for sensitive detection of thrombin using fluorescent quantum dots as labeling probes

“…The concentration change of thrombin in blood is associated with disease such as Alzheimer disease [48] and acute coronary syndromes [49]. Multiple methods have been developed for thrombin detection, which include fluorescence spectroscopy [11,[50][51][52][53][54], surface enhanced Raman scattering (SERS) [55], and electrochemistry [13,15,18]. However, sensitive, simple, and rapid homogeneous assay of thrombin is still needed in clinical diagnosis.…”

“…Compared to antibody, aptamers show certain advantages including automated synthesis, easy modification, and good chemical stability during long-term storage. So far, aptamers as recognition units are used in analytical methods, which mainly include fluorescence [7][8][9][10][11][12], electrochemistry [13][14][15][16][17][18][19], absorbance [20], colorimetric [21][22][23][24][25], and electrochemiluminescence (ECL) [26][27][28][29][30][31][32] etc.…”

l-Arginine-assisted electrochemical fabrication of hierarchical gold dendrites with improved electrocatalytic activity

“…To date, many researches were conducted for the fabrication of Au dendritic nanostructures [26][27][28][29]. For instance, O'Mullane et al synthesized Au dendritic structures by controlling the electrodeposition potential and the introduction of Pb(CH 3 COO) 2 [27].…”

“…In another example, Xu's group prepared Au dendrites onto an Electronic supplementary material The online version of this article (doi:10.1007/s10008-015-2924-6) contains supplementary material, which is available to authorized users. indium tin oxide electrode through controlling the electrodeposition potentials [29].…”

Thrombin detection using a piezoelectric aptamer-linked immunosorbent assay

“…As of March 2013, there were 578 NCBI results when using the search terms ''aptamer'' and ''thrombin'' together. The majority of these publications demonstrate variations of thrombin detection methodologies, including fluorescence [5,31], quantum dots [32], colorimetry [33], electrochemistry [34], and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) [35].…”