title: Fabrication of an electrochemical nanoaptasensor based on AuNPs for ultrasensitive determination of cocaine in serum sample.
abstract: Herein we describe an ultrasensitive electrochemical nanoaptasensor for the detection of one of the most dangerous narcotic drugs available, cocaine. The nanoaptasensor was constructed by the covalent attachment of a 5'-NH2-3'-gold nanoparticles terminated aptamer on the surface of a glassy carbon electrode which was deposited with gold nanoparticles (AuNPs/GCE). It is worth noting that the interaction of the cysteamine stable self-assembled monolayer on the AuNPs/GCE surface and the covalent attachment of terephthalaldehyde via amide coupling with the amine groups in the cysteamine and aptamer, respectively, resulted in the covalent attachment of the aptamer to AuNPs/GCE. The presence of gold nanoparticles both on surface of the glassy carbon electrode and in the end of the aptamer, can provide advantages such as increase of active surface area, high acceleration of the electron transfer and improved electrochemical signal, respectively. The decrease in the peak current of [Fe(CN)6](3-/4-) as the probe redox with increase of cocaine concentration, in differential pulse voltammetry as the measuring technique, from 5 pM up to 5 nM was linear and an unprecedented detection limit of 0.5pM was yielded. Furthermore, the effect of some common analgesic drugs as the potential interferents were investigated and also, to evaluate practical application of the proposed nanoaptasensor human blood serum sample as a real sample was used. Simple preparation, low operation cost, speed and validity are the decisive factors of this method motivating its application to biosensing investigation.
authors.affiliation: Department of Chemistry, Ilam University, Ilam, Iran. Electronic address: mahmoudroushani@yahoo.com.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Roushani
authors.affiliation: Department of Chemistry, Ilam University, Ilam, Iran.
authors.forename: Faezeh
authors.initials: F
authors.lastname: Shahdost-Fard
mesh_terms: D003042:Cocaine / Q000097:blood*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D012680:Sensitivity and Specificity
chemical_list: D006046:Gold; D003042:Cocaine
keywords: Cocaine; Covalently attachment of aptamer; Deposition of AuNPs; Electrochemical nanoaptasensor