Highly sensitive, direct and real-time detection of silver nanowires by using a quartz crystal microbalance

For several decades, silver nanomaterials (AgNMs) have been used in various research areas and commercial products. Among the many AgNMs, silver nanowires (AgNWs) are one of the mostly widely used nanomaterials due to their high electrical and thermal conductivity. However, recent studies have investigated the toxicity of AgNWs. For this reason, it is necessary to develop a successful detection method of AgNWs for protecting human health. In this study, label-free, highly sensitive, direct, and real-time detection of AgNWs is performed for the first time. The detection mechanism is based on the resonance frequency shift upon the mass change from the hybridization between the probe DNA on the electrode and the linker DNA attached on AgNWs. The frequency shift is measured by using a quartz crystal microbalance. We are able to detect 1 ng ml^-1 of AgNWs in deionized water in real-time. Moreover, our detection method can selectively detect AgNWs among other types of one-dimensional nanomaterials and can also be applied to detection in drinking water.