Soon after this study, the Chang laboratory presented a livecell
Cu+ responsive fluorescent probe called Coppersensor-1
(CS1).168,174 CS1 is composed of a boron-dipyrromethene
(BODIPY) dye platform and a thioether-rich receptor
chemically similar to the azatetratiocrown used by CTAP-1.
CS1 is excited and emits in the visible region, offering
decreased phototoxicity as compared to CTAP-1, and it
undergoes a greater increase in fluorescence intensity in the
presence of Cu+ (10-fold vs 4.6-fold). Using CS1, dynamic
changes in copper pools could be visualized in real time during
Cu+ uptake of HEK 293T cells under acute copper overload.168
However, some challenges associated with the use of this sensor
in neuronal and glial cell lines treated with CuCl2 or
Cu(II)(gtsm) were identified in a recent study by Price et al.,
including pH sensitivity and lysosomal uptake