Quantification of Zika virus using a colloidal gold nanoparticle-based immunosensor and Fourier-transform infrared spectroscopy.

Zika virus (ZIKV) is an arthropod-borne virus that has spread worldwide and is the etiological agent of Zika fever, a disease of global concern distinguished by mild symptoms and recently linked to a congenital syndrome in neonates. Microcephaly, hydrocephalus, ocular deformations, and meningoencephalitis characterize this disease. The plaque assay is the gold standard used in scientific research laboratories to quantify the virus titer on a sample and assess their relationship with the infectious dosage. However, it requires costly infrastructure and specialized technical training. In this study, a nano-immunosensor based on gold nanoparticles was developed to detect Zika virus using FTIR spectroscopy. Three calibration curves were established to estimate ZIKV titers by measuring the intensity of absorption bands associated with functional groups in viral samples at different concentrations. The detection sensitivity ranged from 5 × 10⁴ to 5 × 10⁷ PFU/mL for the lipid group (CO, 1750 cm⁻¹), 5 × 10 ³ to 5 × 10⁷ PFU/mL for the protein group (amide I, 1680 cm⁻¹), and 5 × 10⁵ to 2.2 × 10⁸ PFU/mL for the carbohydrate group (C-O, 860 cm⁻¹). The proposed method highlights the potential of the colloidal immunosensor for the quantification of the Zika virus.