Rapid detection of herpes simplex virus types 1 and 2 using a G-quadruplex aptamer-based biosensor

Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), which cause oral and genital herpes in humans, are prevalent worldwide. ELISA, real-time PCR, and cytological assays are conventional methods for detecting these viruses, but they are expensive and time-consuming. The main purpose of this study was to design a specific G-quadruplex aptamer for the simple and rapid detection of HSV-1 and HSV-2. In this study, a specific aptamer was designed using bioinformatics tools for binding to the glycoprotein gD in HSV-1 and HSV-2. After evaluating the binding of the aptamer to gD, based on the stability scores of the secondary and tertiary structures and molecular docking, the aptamer AptNR88 was selected, and its binding to the target protein was confirmed experimentally using a colorimetric system with gold nanoparticles. Gold nanoparticles with an average size of 30 nm were synthesized, and the AptNR88 was coated on them through hydrogen bonds and electrostatic interactions. The concentration of AptNR88 was subsequently optimized for resistance against salt-induced aggregation. The color changes of gold nanoparticles from red to purple due to salt aggregation were observed only in the presence of the AptNR88-virus complex after 15 min. These results confirmed the specific binding of AptNR88 to the gD of HSV-1 and HSV-2. The limit of detection (LOD) for AptNR88 was approximately 11.7 copies/ml for HSV-1 and 15.7 copies/ml for HSV-2. These results indicate that the designed aptamer for detecting these two viruses is sufficiently sensitive and specific.