The first near-IR fluorescent turn-on sensor for the detection of nitroxyl (HNO), the one-electron reduced form of nitric oxide (NO), is reported. The new copper-based probe, CuDHX1, contains a dihydroxanthene (DHX) fluorophore and a cyclam deriv. as a Cu(II) binding site. Upon reaction with HNO, CuDHX1 displays a five-fold fluorescence turn-on in cuvettes and is selective for HNO over thiols and reactive nitrogen and oxygen species. CuDHX1 can detect exogenously applied HNO in live mammalian cells and in conjunction with the zinc-specific, green-fluorescent sensor ZP1 can perform multicolor/multianalyte microscopic imaging. These studies reveal that HNO treatment elicits an increase in the concn. of intracellular mobile zinc.
Raffaella Buonsanti, Anna Loiudice, Petru Pasquale Albertini, Jan Vávra, Gaétan Philippe Louis Ramona
Ivo Furno, Fabio Avino, Rita Agus, Lorenzo Ibba