Visual detection of Ca2+based on aggregation-induced emission of Au(i)–Cys complexes with superb selectivity

A label-free optical probe was developed for Ca(2+) detection based on the aggregation-induced emission property of Au(i)-thiolate complexes. Upon incubation with Ca(2+), the Au(I)-cysteine complexes rapidly aggregated through Cys-Ca(2+) interaction, resulting in a luminescent emission of the complexes. The label-free probe was low cost, simple in design and fast in response.