A reusable impedimetric aptasensor for detection of thrombin employing a graphite-epoxy composite electrode.
Here, we report the application of a label-free electrochemical aptasensor based on a graphite-epoxy composite electrode for the detection of thrombin; in this work, aptamers were immobilized onto the electrodes surface using wet physical adsorption. The detection principle is based on the changes of the interfacial properties of the electrode; these were probed in the presence of the reversible redox couple [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) using impedance measurements. The electrode surface was partially blocked due to formation of aptamer-thrombin complex, resulting in an increase of the interfacial electron-transfer resistance detected by Electrochemical Impedance Spectroscopy (EIS). The aptasensor showed a linear response for thrombin in the range of 7.5 pM to 75 pM and a detection limit of 4.5 pM. The aptasensor was regenerated by breaking the complex formed between the aptamer and thrombin using 2.0 M NaCl solution at 42 °C, showing its operation for different cycles. The interference response caused by main proteins in serum has been characterized.
Department of Chemistry, Universitat Autònoma de Barcelona, Bellaterra 08193, Spain. cristina.ocana@uab.es
Cristina
C
Ocaña
Mercè
M
Pacios
Manel
M
del Valle
D052157:Aptamers, Nucleotide / Q000737:chemistry*; D058266:Dielectric Spectroscopy; D004566:Electrodes; D004853:Epoxy Resins / Q000737:chemistry*; D005295:Ferrocyanides / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D010084:Oxidation-Reduction; D013917:Thrombin / Q000032:analysis*
D052157:Aptamers, Nucleotide; D004853:Epoxy Resins; D005295:Ferrocyanides; C081676:thrombin aptamer; D006108:Graphite; D013917:Thrombin; C020354:hexacyanoferrate II