Fabrication of AuNPs/MWCNTS/Chitosan Nanocomposite for the Electrochemical Aptasensing of Cadmium in Water

Autor: Selma Rabai, Ahlem Teniou, Gaëlle Catanante, Messaoud Benounis, Jean-Louis Marty, Amina Rhouati
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Sensors, Vol 22, Iss 1, p 105 (2021)
Druh dokumentu: article
ISSN: 1424-8220
DOI: 10.3390/s22010105
Popis: Cadmium (Cd2+) is one of the most toxic heavy metals causing serious health problems; thus, designing accurate analytical methods for monitoring such pollutants is highly urgent. Herein, we report a label-free electrochemical aptasensor for cadmium detection in water. For this, a nanocomposite combining the advantages of gold nanoparticles (AuNPs), carbon nanotubes (CNTs) and chitosan (Cs) was constructed and used as immobilization support for the cadmium aptamer. First, the surface of a glassy carbon electrode (GCE) was modified with CNTs-CS. Then, AuNPs were deposited on CNTs-CS/GCE using chrono-amperometry. Finally, the immobilization of the amino-modified Cd-aptamer was achieved via glutaraldehyde cross-linking. The different synthesis steps of the AuNPs/CNTs/CS nano assembly were characterized by cyclic voltammetry (CV). Electrochemical impedance spectroscopy (EIS) was employed for cadmium determination. The proposed biosensor exhibited excellent performances for cadmium detection at a low applied potential (−0.5 V) with a high sensitivity (1.2 KΩ·M−1), a detection limit of 0.02 pM and a wide linear range (10−13–10−4 M). Moreover, the aptasensor showed a good selectivity against the interfering ions: Pb2+; Hg2+ and Zn2+. Our electrochemical biosensor provides a simple and sensitive approach for Cd2+ detection in aqueous solutions, with promising applications in the monitoring of trace amounts of heavy metals in real samples.
Databáze: Directory of Open Access Journals
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