DNA-stabilized silver nanoclusters with guanine-enhanced fluorescence as a novel indicator for enzymatic detection of cholesterol

Abstract

A novel silver nanocluster is synthesized using a DNA template with short guanine at the 3′-end of a DNA scaffold to enhance the fluorescence intensity. The obtained DNA-stabilized silver nanoclusters (G-DNA-Ag NCs) are found to exhibit a strong red fluorescence at 605 nm and its fluorescence can be sensitively quenched by H₂O₂. This allows us to develop a new enzymatic method for fluorescent detection of cholesterol through oxidation by cholesterol oxidase which can generate H₂O₂. The present method is convenient without the need for complicated operations, and demonstrates desirable selectivity with no interferences from species such as ascorbic acid, glucose and urea. It shows a linear detection range for cholesterol from 0.2 to 200 μM with a detection limit of 0.15 μM.