A label-free electrochemical biosensor based on rGO/Ppy nanocomposite for detection of Herpes simplex virus type 1.

The herpes simplex virus type 1 (HSV-1) is a prevalent herpes virus found in many regions worldwide, and it infects only humans as its natural hosts. These viruses cause a wide range of acute, latent, and chronic infections in humans, as the virus can cause latent infections as well as diseases such as primary and recurrent oropharyngeal disease, primary and recurrent genital disease, and herpes simplex infection. Therefore, a fast response, cost-effective, sensitive, and selective detection method for HSV-1 is much needed. Here, we present an electrochemical biosensor that is sensitive and selective for the accurate measurement of HSV-1. The glassy carbon electrode was coated with a reduced graphene oxide and polypyrrole nanocomposite (rGO/Ppy-NCs) for modification. The next step involved linking a specific antisense single-stranded DNA oligonucleotide for HSV-1 to the rGO/Ppy-NCs through a π-stacking interaction. The process of DNA hybridization was assessed through the measurement of changes in the free guanine peak current with changing ssDNA target concentrations by employing the method called differential pulse voltammetry (DPV). This biosensor showed a consistent response to synthetic ssDNA target, ranging from 1.0 × 10^-15 to 1.0 × 10^-11 M, with a detection limit of 0.83 fM. The biosensor's performance was put to the test using a cell culture sample positive for HSV-1, a positive HTLV-1 sample, and a PCR-confirmed negative sample. The obtained results exhibited excellent detection potential of the proposed biosensor as a sensitive and specific biosensing system.