DNA Based Gold Nanoparticles Colorimetric Sensors for Sensitive and Selective Detection of Ag(I) Ions

摘要

Recently, colorimetric sensors have drawn more and more attention to decrease the experimental cost, simplify the sensing process, and even only utilize naked eyes instead of the complex instruments. One of the most popular colorimetric techniques makes use of gold nanoparticles (AuNPs) as reporting probes. AuNPs are easy to synthesize and display high extinction and strong size-and distance-dependence characters. Once the AuNPs are induced to aggregate, their plasmon peaks at 520 nm decrease and the ones at 650 nm increaseand the color embodies a visible change from red to purple even blue. It has been proved that using either unlabeled or labeled AuNPs as colorimetric reporters, unfolded single strand deoxyribonucleic acid (ssDNA) can be well discriminated from the folded ssDNA or the double strand DNA (dsDNA) [1, 2]. A lot of DNA based AuNPs colorimetric sensors are thus developed, including DNA sensors [1,2], DNAzyme sensors [3] and aptasensors [4]. The targets cover the metal ions, small molecules and proteins, significantly extending the applications of AuNPs based biosensing strategies.