NIOBIUM OXIDE GENOSENSOR DEVELOPMENT FOR VIRAL DETECTION

Genosensors aroused interest in the biosensing and diagnostic areas, as they are low cost, high specificity, and fast target detection [1]. Besides, they can also be associated with nanostructured materials, increasing sensitivity. This work's objective was to develop an electrochemical genosensor for viral detection. For this, nanostructured niobium oxide [2] was supported on fluorine-doped tin oxide glass to build an electrode,  which was functionalized with chitosan and glutaraldehyde by dip coating (immersion speed: 420 mm/min; immersion: 300 s; withdrawal speed: 300 mm/min), then synthetic amino-modified ssDNA-probe (5 µL; 100 µM, 30 minutes) were immobilized by cross-link and the surface was blocked with bovine serum albumin (BSA, 1%, overnight). Finally, for the hybridization step, samples containing ssDNA-target (5 µL; 100 µM) were added to the surface and incubated for 45 minutes at 25ºC in a wet chamber. The characterization was carried out by electrochemical impedance spectroscopy (EIS) assays using K₃[Fe(CN)₆]/K₄[Fe(CN)₆] 10 mM in saline phosphate buffer as electrolyte. From EIS results, changes in charge transfer resistance (R_ct) can be observed as functionalization steps were conducted. Finally, the hybridization event showed an increase of 57% in the R_ct compared to the blocked sample. The results showed that the proposed platform has the potential to be used in biosensing applications, since the layers used to construct the genosensors had different interactions with the electrolyte, especially when DNA was added, creating a repulsion effect between the electrode surface and the electroactive species of the electrolyte. Further experiments must be conducted to determine the figures of merit, in order to validate the proposed nanostructured niobium oxide genosensor.