Flow injection amperometric sandwich-type electrochemical aptasensor for the determination of adenocarcinoma gastric cancer cell using aptamer-Au@Ag nanoparticles as labeled aptamer. (20th August 2017)

• Record Type: Journal Article
• Authors: Amouzadeh Tabrizi, Mahmoud; Shamsipur, Mojtaba; Saber, Reza; Sarkar, Saeed; Sherkatkhameneh, Narjes
• Is Part Of: Electrochimica acta. Volume 246(2017)
• Page Start: 1147
• Page End: 1154
• Publication Date: 2017-08-20
• Subjects: Flow injection -- Sandwich-type aptasensor -- aptamerAGS-Au@Ag nanoparticles -- AGS cancer cell; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2017.06.115
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Abstract: Herein, a flow injection amperometric aptasensor was developed for the determination of adenocarcinoma gastric cell (AGS) cancer cells in presence of hydrogen peroxide (H2 O2 ). For this purpose, the aptamer/gold-core and silver-shell (Au@Ag) nanoparticles were synthesized as the secondary labeled aptamers using thiolated cytosine-rich aptamer. First, the thiolated aptamer was self-assembled to the gold nanoparticles (AuNPs) surface through S-AuNPs bonds. Then, this cytosine-rich aptamer/AuNPs were added to the Ag + solution to form (C-Ag + -C)n complexes. The adsorbed Ag + ions on the aptamer were then reduced to Ag shell on the surface of AuNPs core by thyme leaves extract as a green reducing agent. The surface of screen printed electrode (SPE) was also modified with multiwall carbon nanotube decorated with gold nanoparticles (MWCNT-Aunano ) as a nano-platform to increase the surface area to immobilize primary thiolated non-cytosine-rich aptamer and improve electron transfer property of electrode. The MWCNT-Aunano, AuNPs and aptamerAGS -Au@Ag nanoparticles were characterized using transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to confirm the stepwise changes in the electrochemical surface properties of the electrode. The determination processes were performed in a flow injection microchannel device under the optimized conditions. The selective interactions between primary aptamer/AGS/secondary aptamer-Au@Ag nanoparticles led to increase in the response of aptasensor to AGS cancer cell in presence of 0.1 mM H2 O2 because of the electrocatalytic activity of Au@Ag nanoparticles toward the reduction of H2 O2 . The proposed sandwich-type electrochemical aptasensor exhibited a good response to the logarithmic value of AGS cancer cells in the range of 1 × 10 1 to 5 × 10 5 cells mL −1 with a low limit of detection of 6 cells mL −1 in the flow injection amperometric determination process. The target-aptamer dissociation constant (kd ) was also calculated based on the change in current to be 104 cells mL −1 . The fabricated sandwich-type electrochemical aptasensor was applied for the determination of AGS cancer cell in the human serum sample. The proposed sandwich-type aptasensor exhibited good linear range responsibility, selectivity, and stability.