Design of a two-photon fluorescent probe for selective recognition of Au(III) over Au(I) and its application of imaging in vitro and in vivo.

A highly selective two-photon fluorescent probe (PyCM-1) for Au3+ was developed with distinct "turn on" fluorescence response, low detection limit (22nM) and large two-photon absorption cross-sections (696 GM at 860nm). Its high selectivity for Au3+ over Au+ was achieved via the modification on the type of coordination atoms in the Schiff base receptor. Co-staining experiments showed that the probe PyCM-1 could co-localize specifically with mitochondria. Moreover, the two-photon confocal fluorescence imaging results demonstrated the probe's capability for visualizing Au3+in vitro and in vivo.