Influence of citrate buffer and flash heating in enhancing the sensitivity of ratiometric genosensing of Hepatitis C virus using plasmonic gold nanoparticles

Gold nanoparticles (Au NPs) based technology has been shown to possess enormous potential in the viral nucleic acid diagnosis. Despite significant advancement in this domain, the existing literature reveals the diversity in the conditions employed for hybridization and tagging of thiolated nucleic acid probes over the Au NPs. Here we employ the probe sequence derived from the Hepatitis C virus to identify the optimal hybridization and thiol-Au NP tagging conditions. In a typical polymerase chain reaction, the probes are initially subjected to flash heating at elevated temperatures to obtain efficient annealing. Motivated by this, in the current study, the hybridization between the target and the antisense oligonucleotide (ASO) has been studied at 65 °C with and without employing flash heating at temperatures from 75 to 95 °C. Besides, the efficiency of the thiolated ASO’s tagging over the Au NPs with and without citrate buffer has been explored. The study has revealed the beneficial role of flash heating at 95 °C for efficient hybridization and the presence of citrate buffer for rapid and effective thiol tagging over the Au NPs. The combinatorial effect of these conditions has been found to be advantageous in enhancing the sensitivity of ratiometric genosensing using Au NPs.