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

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 mu M with a detection limit of 0.15 mu M.