an impedimetric genosensor for ultrasensitive detection of sars-cov-2 genome based on 3d reduced graphene oxide and gold nanoparticle composite

Nowadays the severe acute respiratory syndrome coronavirus 2 (sars-cov-2) has become an endemic disease throughout the world on the other hand intensive worldwide vaccination programs decreased the severity of the affection but early virus detection and disease diagnosis are still important healthcare management of infectious disease control. therefore, in this research, we introduce an electrochemical genosensor based on a dna probe that can hybridize directly to the viral genome or its transcripts and therefore does not need cdna synthesis following rna extraction from patient samples, a necessary and challenging step in routine rna virus detection methods like real-time pcr. altogether, in this research, an electrochemical biosensor based on a virus-specific probe with thiol modification was designed and immobilization of the probe was carried out through self-assembly by thiol binding on reduced graphene oxide (rgo) and gold nanoparticles composite-modified pencil graphite electrode (pge). the hybridizations of probe and target sequences were analyzed by electrochemical impedance spectroscopy (eis) and cyclic voltammetry (cv) methods. the linear range was found to be within 10-12 - 10-6 m and the limit of detection (lod) was at 3× 10 -13 m. the time of 20 minutes was chosen as the optimal hybridization time. the results showed that the fabricated biosensor can be recovered and reused up to 6 times. this means significant time, and expense savings when compared with other conventional detection methods for this virus. therefore, this biosensor is suggested for clinical applications especially when time and sensitivity are the most limited elements.