Bioelectrode applied to diagnosis of cardiac disease.

This paper describes the assembly of a bioelectrode based on poly(3-aminophenol) and anti-troponin T antibody for recognition of troponin T, which is a specific biomarker for diagnosis of acute myocardial infarction. This disease causes loss of cellular components, allowing the output of molecules such as troponin T. This proteic component acts as biomarker for diagnosis of acute myocardial infarction due to their high sensitivity and specificity. Poly(3-aminophenol) was electrodeposited onto fluorine doped tin oxide (FTO) coated glass and characterized by spectroscopic methods (UV-Visible, fluorescence, infrared), electrochemical methods (cyclic voltammetry and electrochemical impedance spectroscopy) and morphological methods (laser interferometry, field emission scanning electronic microscopy, and atomic force microscopy). UV/Vis analysis indicated that poly(3-aminophenol) presents extension of conjugation, in according with fluorescence studies. Electrochemical studies indicated that poly(3-aminophenol) electrodeposited in FTO is a material with passivating characteristics for anions and capacity of retaining cationic compounds. Laser interferometry showed that poly(3-aminophenol) covers the FTO surface with a thickness off 375 ± 75 nm. Surface images by FE-SEM and AFM have shown a full coverage on the FTO by the polymer film. The incorporation of anti-troponin T antibody on FTO electrode modified with poly(3-aminophenol) allowed effective and selective detection of cardiac biomarker troponin T, by electrochemical impedance spectroscopy (label free) and by photoluminescence, based on CdSe/ZnS quantum dots. This research shows the step by step assembly of the bioelectrode, used for detection of troponin T by impedimetric and fluorescence methods, opening the opportunity for its use in the diagnosis of others diseases.