Desenvolvimento de um biossensor impedimétrico de DNA com silsesquioxano para detecção label-free do vírus zika

Abstract

Zika virus (ZIKV) detection has become a global health challenge in recent years due to its rapid geographical expansion associated with the increase of neurological abnormalities such as Guillain-Barré syndrome and Microcephaly. Currently, the techniques for ZIKV diagnosis require labor intense, costly and lengthy tests using sophisticated equipment; moreover, false positives occur. This work aimed to develop an impedimetric DNA biosensor for label-free detection of this virus. For this, a platform consisting of an oxidized glassy carbon electrode (ox-ECV) modified with gold nanoparticles functionalized by the polyelectrolyte 3-npropylpyridine chloride silsesquioxane (AuNPs-SiPy) was obtained. This nanohybrid was characterized by UV-VIS, DLS, FTIR, Raman and XRD measurements, and the nanohybrid modified carbon glass electrode, ox-ECV-[AuNPs-SiPy] by electrochemical techniques. After the immobilization of a specific synthetic oligonucleotide of the ZIKV genome with thiol grouping (ZIKV1) on this electrode, the biosensor ox-ECV-[AuNPs-SiPy]/ZIKV1 was formed, whose modification steps were optimized through univariate and multivariate. The optimized biosensor was characterized by electrochemical impedance spectroscopy, cyclic voltammetry and atomic force microscopy. The recognition of the ZIKV target ssDNA was monitored by the variation transfer resistance (ΔRct) of the electrochemical marker used ([Fe(CN)6] 4- / 3- ) and the roughness (Rq) of the electrode surface. This biosensor presented a detection limit (LOD) of 0.41 pmol L-1 with a linear range of 1.0 x 10-12 – 1.0 x 10-6 mol L-1 . The proposed device also presents to be stable for 90 days (98.02 % of the initial response), sensitive and selective to quantify the target of ZIKV in serum samples, and is therefore a promising tool for the early diagnosis of ZIKV.