Amperometric Immunosensor Based on a Protein A/Deposited Gold Nanocrystals Modified Electrode for Carbofuran Detection

Abstract

In this paper, an amperometric immunosensor modified with protein A/deposited gold nanocrystals (DpAu) was developed for the ultrasensitive detection of carbofuran residues. First, DpAu were electrodeposited onto the Au electrode surface to absorb protein A (PA) and improve the electrode conductivity. Then PA was dropped onto the surface of DpAu film, used for binding antibody Fc fragments. Next, anti-carbofuran monoclonal antibody was immobilized on the PA modified electrode. Finally, bovine serum albumin (BSA) was employed to block the possible remaining active sites avoiding any nonspecific adsorption. The fabrication procedure of the immunosensor was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), respectively. With the excellent electroconductivity of DpAu and the PA’s oriented immobilization of antibodies, a highly efficient immuno-reaction and detection sensitivity could be achieved. The influences of the electrodeposition time of DpAu, pH of the detection solution and incubation time on the current response of the fabricated immunosensor were investigated. Under optimized conditions, the current response was proportional to the concentration of carbofuran which ranged from 1 to 100 ng/mL and 100 ng/mL to 100 μg/mL. The detection limit was 0.1924 ng/mL. The proposed carbofuran immnuosensor exhibited high specificity, reproducibility, stability and regeneration performance, which may open a new door for ultrasensitive detection of carbofuran residues in vegetables and fruits.

Amperometric immunosensor based on deposited gold nanocrystals/4,4′-thiobisbenzenethiol for determination of carbofuran

“…After anti-carbofuran/DpAu/DMDPSE/Au was blocked with BSA, Rct increased slightly to 22.9 kU (curve e). When the immunosensor was used to detect carbofuran, Rct remarkably increased to 35.2 kU (curve f), which was in good agreement with the previous reports Sun, Zhu, et al, 2011). Therefore, we can confirm from changes of Rct that different species are immobilized on the surface of electrode.…”

“…In our earlier work, we have also shown that the deposited gold nanocrystals (DpAu) formed a uniformer and porous film onto the surface of electrode compared with the colloidal gold nanoparticles (GNPs). Moreover, the DpAu film could be controlled through the concentration of gold chloride tetrahydrate (HAuCl 4 ) solution and the electrodeposition time, which is more convenient than GNPs film (Sun, Zhu, & Wang, 2011).…”

Electrochemical Aptatoxisensor Responses on Nanocomposites Containing Electro-Deposited Silver Nanoparticles on Poly(Propyleneimine) Dendrimer for the Detection of Microcystin-LR in Freshwater

“…However, the DNA aptamer oligonucleotides may not attach to the surface exclusively through the sulfur atom of the thiol group as nitrogen-containing nucleotide side chains can and may also interact directly with the AgNPs on the GCE|SDD–Co(II)|AgNPs surface. To diminish such non-specific binding of the DNA aptamer to the AgNPs on the surface of GCE|SDD–Co(II)|AgNPs, 6-mercapto-1-hexanol (MCH) was used [34]. As a result, only thiolated DNA aptamers are adsorbed onto the surface of the modified GCE|SDD–Co(II)|AgNPs through the thiol sulfur atom as nonspecifically bound DNA aptamers are removed by the MCH treatment [34,35].…”

“…To diminish such non-specific binding of the DNA aptamer to the AgNPs on the surface of GCE|SDD–Co(II)|AgNPs, 6-mercapto-1-hexanol (MCH) was used [34]. As a result, only thiolated DNA aptamers are adsorbed onto the surface of the modified GCE|SDD–Co(II)|AgNPs through the thiol sulfur atom as nonspecifically bound DNA aptamers are removed by the MCH treatment [34,35]. …”

Construction of an impedimetric immunosensor for label-free detecting carbofuran residual in agricultural and environmental samples

“…Many techniques for the determination of carbofuran have been developed including gas chromatography (GC) (Leppert, Markle, & Helt, 1983), high performance liquid chromatography (HPLC) (Nogueira, Sandra, & Sandra, 2004), liquid chromatography-mass spectrometry (LC-MS) (Honing, Barcel o, van Baar, & Brinkman, 1995;Soler et al, 2007), gas chromatography-mass spectrometer (GCeMS) (Petropoulou, Gikas, Tsarbopoulos, & Siskos, 2006), chemiluminescence (P erez-Ruiz, Martínez-Lozano, Tom as, & Martín, 2002), enzyme-linked immunosorbent assay (ELISA) (Yang et al, 2008;Moreno et al, 2001;Abad, Moreno, & Montoya, 1997;Jourdan, Ardid, Chapuy, Eschalier, & Bars, 1995), fluorimetry (Li, Zhang, Zhao, & Hu, 2010), amperometric immunosensor (Sun, Zhu, & Wang, 2011), and microcantilever sensor (Wang, Wang, Liu, & Hu, 2011). Carbofuran is thermally unstable and decomposes to the phenol under the usual gas chromatography conditions (Li ska & Slobodík, 1996).…”