Size- and Distance-Dependent Nanoparticle Surface-Energy Transfer (NSET) Method for Selective Sensing of Hepatitis C Virus RNA

We report size- and distance-dependent surface-energy transfer (SET) properties of gold nanoparticles for recognizing hepatitis C virus (HCV) RNA sequence sensitively and selectively (single-base mutations) in a homogeneous formal. We have demonstrated that quenching efficiency increases by three orders of magnitude, as the particle size increases from 5 to 70 nm. Due to this extraordinarily high K-SV, nanoparticle SET (NSET) detection limit can be as low as 300 fM concentration of RNA, depending on the size of gold nanoparticle. We have shown that the distance-dependent quenching efficiency is highly dependent oil the particle size and the distance at which the energy-transfer efficiency is 50%. ranges all the way front 8 nm, which is very close to the accessible distance of conventional Forster resonance energy transfer (FRET), to about 40 nm by choosing gold nanoparticles of different diameters. Our result points out that dipole-to-metal-particle energy transfer and NSET models provide a better description of the distance dependence of the quenching efficiencies for 8 nm gold nanQpartjCle but agreement is poor for 40 and 70 nm gold nanoparticles, for which the measured values were always larger than the predicted ones.