Abstract
We report the distance-dependent fluorescence behavior of Au-DNA conjugates prepared by equilibrating the phos-phine-stabilized gold nanoparticles (AuNPs) of 10-nm size with the designed rigid spacer double-stranded DNA consisting of thiol-modified target and Cy3-labelled complementary probe of different lengths (5 to 20 nm). The products were immobilized onto a MPTMS (3- mercaptopropyltrimethoxysilane)-modified glass substrate and were finally excited with a 532-nm laser source. Fluorescence quenching in both solution and solid platforms was assessed via disulfide bond cleavage between Au and DNA-Cy3 using mercaptoethanol. Successful and effective cleavage revealed by UV-vis absorption and fluorescence profiles was achieved in just only a few minutes.