Autor(es): Soares, Juliana C. ; Iwaki, Leonardo E. O. ; Soares, Andrey C. ; Rodrigues, Valquiria C. ; Melendez, Matias Eliseo ; Fregnani, José Humberto T. G. ; Reis, R. M. ; Carvalho, André Lopes ; Corrêa, Daniel S. ; Oliveira Júnior, Osvaldo N.
Data: 2017
Identificador Persistente: https://hdl.handle.net/1822/48956
Origem: RepositóriUM - Universidade do Minho
We report the fabrication of immunosensors based on nanostructured mats of electrospun nanofibers of polyamide 6 and poly(allylamine hydrochloride) coated either with multiwalled carbon nanotubes (MWCNTs) or gold nanoparticles (AuNPs), whose three-dimensional structure was suitable for the immobilization of anti-CA19-9 antibodies to detect the pancreatic cancer biomarker CA19-9. Using impedance spectroscopy, the sensing platform was able to detect CA19-9 with a detection limit of 1.84 and 1.57 U mL-1 for the nanostructured architectures containing MWCNTs and AuNPs, respectively. The high sensitivity achieved can be attributed to the irreversible adsorption between antibodies and antigens, as confirmed with polarization-modulated infrared reflection absorption spectroscopy. The adsorption mechanism was typical Langmuir-Freundlich processes. The high sensitivity and selectivity of the immunosensors were also explored in tests with blood serum from patients with distinct concentrations of CA19-9, for which the impedance spectra data were processed with a multidimensional projection technique. The robustness of the immunosensors in dealing with patient samples without suffering interference from analytes present in biological fluids is promising for a simple, effective diagnosis of pancreatic cancer at early stages.
