title: A label-free aptasensor based on polyethyleneimine wrapped carbon nanotubes in situ formed gold nanoparticles as signal probe for highly sensitive detection of dopamine.
abstract: Herein, a highly sensitive and selective aptamer biosensor for quantitative detection of a model target, dopamine (DA), was developed by using a gold (Au) electrode modified with highly dispersed gold nanoparticles (AuNPs) and acid-oxidized carbon nanotubes (CNTs-COOH) functionalized with polyethyleneimine (PEI). Amine-terminated12-mercaptureprobe (ssDNA1) as a capture probe and specific DA-aptamer (ssDNA2) as a detection probe was immobilized on the surface of a modified electrode via the formation of covalent amide bond and hybridization, respectively. Methylene blue (MB) was used as the redox probe, which was intercalated into the aptamer through the specific interaction with its guanine bases. In the presence of DA, the interaction between aptamer and DA displaced the MB from the electrode surface, rendering a lowered electrochemical signal attributed to decreased amount of adsorbed MB. The developed electrochemical DA aptasensor showed a good linear response to DA from 5 to 300nM with detection limit of 2.1nM. The biosensor also exhibited satisfactory selectivity and could be successfully used to detect DA in blood serum sample.
authors: Department of Chemistry, Khorramabad Branch, Islamic Azad University, Khorramabad, Iran. Electronic address: Azadbakht.a@gmail.com.
authors: Azadeh
authors: A
authors: Azadbakht
authors: Department of Chemistry, Ilam University, Ilam, Iran.
authors: Mahmoud
authors: M
authors: Roushani
authors: Department of Chemistry, Khorramabad Branch, Islamic Azad University, Khorramabad, Iran.
authors: Amir Reza
authors: AR
authors: Abbasi
authors: Department of Chemistry, Khorramabad Branch, Islamic Azad University, Khorramabad, Iran.
authors: Saeid
authors: S
authors: Menati
authors: Department of Chemistry, Khorramabad Branch, Islamic Azad University, Khorramabad, Iran.
authors: Zohreh
authors: Z
authors: Derikvand
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D004298:Dopamine / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011094:Polyethyleneimine / Q000737:chemistry*; D012680:Sensitivity and Specificity
chemical_list: D052157:Aptamers, Nucleotide; D037742:Nanotubes, Carbon; D006046:Gold; D011094:Polyethyleneimine; D008751:Methylene Blue; D004298:Dopamine
keywords: Aptasensor; Dopamine; Gold nanoparticles; Polyethyleneimine