Silver nanocluster based sensitivity amplification of a quartz crystal microbalance gene sensor

The article describes a quartz crystal microbalance (QCM) biosensor for the determination of nucleic acids via a DNA-templated assembly of silver nanoclusters (AgNCs) which represents a novel way for efficient signal amplification. A QCM was modified with probe DNA to specifically capture target DNA. Then, DNA-templated AgNCs were assembled to enhance the sensitivity of the QCM sensor via Ag(I) ions attached to the DNA skeleton, this followed by hydroquinone-induced reductive formation of the AgNCs. TEM and AFM were used to further confirm the formation of DNA-templated AgNCs. The results showed that frequency response of QCM sensor is up to 87 times larger when using this mode of amplification. A linear relationship was obtained between the frequency response and DNA concentration over the 0.6 to 130 nM range, with a 0.1 nM detection limit. In our perception, this scheme for improved sensitivity provides a straightforward and widely applicable tool for sensing DNA.