Copper(II)-mediated sliver nanoclusters as a fluorescent platform for highly sensitive detection of alendronate sodium

Alendronate sodium (ALDS) is an important and regularly used medicine in clinical therapy of osteoporosis. In this work, a new analytical method is developed for the detection of ALDS based on a fluorescent platform of copper(II)-mediated silver nanoclusters (AgNCs). Specifically, Cu2+ can selectively bind with DNA-stabilized AgNCs and thus greatly quench their red fluorescence. In the presence of ALDS, their fluorescence can largely recover again owing to the stronger coordination of ALDS with Cu2+. On the basis of such a mechanism, fluorescence “on-off-on” mode of the nanoprobe is applied to detect ALDS in a wide linear range of 800 pM-200 μM, with a detection limit of 100 pM. Compared with previously reported methods, the present approach has significant advantages regard to simplicity, high sensitivity, and a wide detectable concentration range. This method has been successfully applied in ALDS assay in tablets and human body fluids.