Browsing by Author "Dutra, Rosa F."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- An ultrasensitive human cardiac troponin T graphene screen-printed electrode based on electropolymerized-molecularly imprinted conducting polymerPublication . Silva, Bárbara V.M.; Rodríguez, Blanca A.G.; Sales, Goreti; Sotomayor, Maria Del Pilar T.; Dutra, Rosa F.A nano-molecularly imprinted polymer (N-MIP) assembled on a screen-printed electrode for the cardiac troponin T (cTnT) was developed. The biomimetic surface was obtained by a co-polymer matrix as-sembled on the reduced graphene oxide (RGO) electrode surface. The cTnT active sites were engineered using pyrrole and carboxylated pyrrole that was one-step electropolymerized jointly with cTnT by cyclic voltammetry. The stepwise preparation of the biomimetic surface was characterized by cyclic and dif-ferential pulse voltammetries using the ferrocyanide/ferricyanide as redox probe. Structural and mor-phological characterization was also performed. The optimal relation of pyrrole and pyrrole-3-acid car-boxylic to perform the cTnT biomimetic nanosurface was obtained at 1:5 ratio. The analytical perfor-mance of cTnT N-MIP performed by differential pulse voltammetry showed a linear range from 0.01 to 0.1 ng mL-1 (r¼0.995, p«0.01), with a very low limit of detection (0.006 ng mL-1). The synergic effect of conductive polymer and graphene forming 3D structures of reactive sites resulted in a N-MIP with ex-cellent affinity to cTnT binding (KD¼7.3 10-13 mol L-1). The N-MIP proposed is based on a simple method of antibody obtaining with a large potential for point-of-care testing applications.
- Plastic Antibody of Polypyrrole/Multiwall Carbon Nanotubes on Screen-Printed Electrodes for Cystatin C DetectionPublication . Gomes, Rui S.; Gomez-Rodríguez, Blanca Azucena; Fernandes, Ruben; Sales, Goreti; Moreira, Felismina; Dutra, Rosa F.This work reports the design of a novel plastic antibody for cystatin C (Cys-C), an acute kidney injury biomarker, and its application in point-of-care (PoC) testing. The synthetic antibody was obtained by tailoring a molecularly imprinted polymer (MIP) on a carbon screen-printed electrode (SPE). The MIP was obtained by electropolymerizing pyrrole (Py) with carboxylated Py (Py-COOH) in the presence of Cys-C and multiwall carbon nanotubes (MWCNTs). Cys-C was removed from the molecularly imprinted poly(Py) matrix (MPPy) by urea treatment. As a control, a non-imprinted poly(Py) matrix (NPPy) was obtained by the same procedure, but without Cys-C. The assembly of the MIP material was evaluated in situ by Raman spectroscopy and the binding ability of Cys-C was evaluated by the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) electrochemical techniques. The MIP sensor responses were measured by the DPV anodic peaks obtained in the presence of ferro/ferricyanide. The peak currents decreased linearly from 0.5 to 20.0 ng/mL of Cys-C at each 20 min successive incubation and a limit of detection below 0.5 ng/mL was obtained at pH 6.0. The MPPy/SPE was used to analyze Cys-C in spiked serum samples, showing recoveries <3%. This device showed promising features in terms of simplicity, cost and sensitivity for acute kidney injury diagnosis at the point of care.