title: Solid-contact potentiometric aptasensor based on aptamer functionalized carbon nanotubes for the direct determination of proteins.
abstract: A facile, solid-contact selective potentiometric aptasensor exploiting a network of single-walled carbon nanotubes (SWCNT) acting as a transducing element is described in this work. The molecular properties of the SWCNT surface have been modified by covalently linking aptamers as biorecognition elements to the carboxylic groups of the SWCNT walls. As a model system to demonstrate the generic application of the approach, a 15-mer thrombin aptamer interacts with thrombin and the affinity interaction gives rise to a direct potentiometric signal that can be easily recorded within 15 s. The dynamic linear range, with a sensitivity of 8.0 mV/log a(Thr) corresponds to the 10(-7)-10(-6) M range of thrombin concentrations, with a limit of detection of 80 nM. The aptasensor displays selectivity against elastase and bovine serum albumin and is easily regenerated by immersion in 2 M NaCl. The aptasensor demonstrates the capacity of direct detection of the recognition event avoiding the use of labels, mediators, or the addition of further reagents or analyte accumulation.
authors.affiliation: Department of Analytical and Organic Chemistry, Universitat Rovira i Virgili, 43007 Tarragona, Spain.
authors.forename: Ali
authors.initials: A
authors.lastname: Düzgün
authors.forename: Alicia
authors.initials: A
authors.lastname: Maroto
authors.forename: Teresa
authors.initials: T
authors.lastname: Mairal
authors.forename: Ciara
authors.initials: C
authors.lastname: O'Sullivan
authors.forename: F Xavier
authors.initials: FX
authors.lastname: Rius
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D006801:Humans; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011199:Potentiometry / Q000379:methods*; D012680:Sensitivity and Specificity; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D037742:Nanotubes, Carbon; C081676:thrombin aptamer; D013917:Thrombin