Nona Semana Integrada do Instituto de Física de São Carlos

Low-cost biosensors based on screen-printed carbon electrodes modified with carbon black and polyelectrolytes films for detection of cancer biomarkers

Não agendado

20m

Doutorado

Palestrante

Sra Gisela Ibánez-Redín (Instituto de física de São Carlos-USP)

Descrição

Low-cost screen-printed carbon electrodes (SPCEs) modified with the cost-effective material, carbon black (CB), offer unparalleled insights into the development of user-friendly and inexpensive electrochemical devices to detect several analytes of environmental, pharmaceutical, and clinical interest.(1)However, despite these advantages, the capability of this platform of detecting clinical relevant biomarkers at point-of-care remains relatively unexplored. Here, we developed a low-cost electrochemical immunosensor for detecting pancreatic cancer antigen CA 19-9 using home-made SPCEs modified with composites based on CB and positively and negatively charged polyelectrolytes (i.e. polyethyleneimine (PEI) and polyacrylic acid (PAA)). Disposable devices were fabricated using poly(ethylene terephthalate) (PET) substrates and the working electrodes were modified with CB-polyelectrolyte films in layer-by-layer assembly. Stable flexible films were obtained with increased SPCEs surface area and enhanced device electrochemical response as verified using atomic force microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The presence of carboxylic groups at the top layer (CB-PAA) enabled covalent immobilization of anti-CA19-9 antibodies without requiring additional surface functionalization. The concentration of CA19-9 was determined in a label-free protocol by monitoring the decrease in current intensity with the increment of antigen concentration in Fe(CN)63−/Fe(CN)64− by means of differential pulse voltammetry experiments. The resulting devices displayed a low-cost (< US$0.5), high selectivity, reproducibility (RSD= 3.24%) and low limit of detection of 0.02 U mL−1. Finally, the capability of the biosensor to detect CA 19-9 was evaluated in real samples from pancreatic cancer patients. The platform proposed here shows great promise for cancer biomarkers detection in clinical samples, since it is easily fabricated, disposable and relatively inexpensive.

Referências

1 TROJANOWICZ, M.Impact of nanotechnology on design of advanced screen printed electrodes for different analytical applications. Trends in Analytical Chemistry, v.84,pte A,p. 22-47, 2016.