title: A carbon nanotube screen-printed electrode for label-free detection of the human cardiac troponin T.
abstract: Label-free immunosensor based on amine-functionalized carbon nanotubes screen-printed electrode is described for detection of the cardiac troponin T, an important marker of acute myocardial infarction. The disposable sensor was fabricated by tightly squeezing an adhesive carbon ink containing carbon nanotubes onto a polyethylene terephthalate substrate forming a thin film. The use of carbon nanotubes increased the reproducibility and stability of the sensor, and the amine groups permitted nonrandom immobilization of antibodies against cardiac troponin T. Amperometric responses were obtained by differential pulse voltammetry in presence of a ferrocyanide/ferricyanide redox probe after troponin T incubation. The calibration curve indicated a linear response of troponin T between 0.0025 ng mL(-1) and 0.5 ng mL(-1), with a good correlation coefficient (r=0.995; p<0.0001, n=7). The limit of detection (0.0035 ng mL(-1) cardiac troponin T) was lower than any previously described by immunosensors and was comparable with conventional analytical methods. The high reproducibility and clinical range obtained using this immunosensor support its utility as a potential tool for point-of-care acute myocardial infarction diagnostic testing.
authors.affiliation: Biomedical Engineering Laboratory, Federal University of Pernambuco, Av. Prof. Moraes Rego, 1235-Cidade Universitária, 50670-901 Recife, Pernambuco, Brazil.
authors.forename: Bárbara V M
authors.initials: BV
authors.lastname: Silva
authors.forename: Igor T
authors.initials: IT
authors.lastname: Cavalcanti
authors.forename: Mízia M S
authors.initials: MM
authors.lastname: Silva
authors.forename: Rosa F
authors.initials: RF
authors.lastname: Dutra
mesh_terms: D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry / Q000302:isolation & purification; D015374:Biosensing Techniques; D002138:Calibration; D055664:Electrochemical Techniques; D004566:Electrodes; D005292:Ferricyanides / Q000737:chemistry; D005295:Ferrocyanides / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D051379:Mice; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011093:Polyethylene Terephthalates / Q000737:chemistry*; D011327:Printing; D015203:Reproducibility of Results; D020107:Troponin T / Q000097:blood* / Q000302:isolation & purification
chemical_list: D055910:Antibodies, Immobilized; D005292:Ferricyanides; D005295:Ferrocyanides; D037742:Nanotubes, Carbon; D011093:Polyethylene Terephthalates; D020107:Troponin T; C031835:potassium ferrocyanide; C028033:potassium ferricyanide
keywords: Carbon nanotube; Human cardiac troponin T; Immunosensor; Point-of-care testing; Screen-printed electrode