Novel near-infrared Aza-BODIPY-based fluorescent and colorimetric sensor for highly selective detection of Au3+ in aqueous media, human skin and brain cells

A new near-infrared (NIR) fluorescent probe for the determination of Au3+ ions was synthesized by introducing boron dipyrromethene moiety as a fluorophore and attaching it with propyne groups as a Au3+-specific recognition unit. The photophysical properties revealed that the fluorescent emission of the sensor was observed in the NIR region with a wavelength of 713 nm. Furthermore, the sensor exhibited excellent sensitivity to Au3+ ions with fluorescent enhancement behavior in aqueous media and naked-eye observation through a colorimetric change from green to yellow. The detection limit of aza-BDP-Pro was found to be 0.64 µM (0.126 ppm). The probe was successfully utilized for selectively detecting Au3+ ions against other 18 interfering metal ions and tracking Au3+ ions in vivo for imaging application.