Future Directions of Fluorescence Sensors for Cellular Studies

Small-Molecule Fluorescent Probes for Binding- and Activity-Based Sensing of Redox-Active Biological Metals

“…Fluorophores generally require visible excitation and emission wavelengths to avoid cellular autofluorescence and phototoxicity, with more recent interest in near-infrared fluorophores that can enable deeper tissue penetration for in vivo imaging. 25 Commonly used fluorophore scaffolds include coumarin, 1,8-naphthalimide, fluorescein, rhodamine, cyanine, and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY). The recognition domain interacts with the metal ion of interest and elicits a fluorescence response to that specific metal ion.…”

“…86 Dye RAcy (24), an esterase-cleavable rhodamine variant, was established and applied for distinguishing labile Fe(II) in live versus dead human cervical carcinoma cell line (HeLa) and for imaging exogenously added iron in Kunming mice. 87 A camphor variant, CCO (25) was shown to detect Fe(II) changes in HeLa cells treated with FAS, Bpy, buthioninesulfoximine (BSO) as a ferroptosis inducer, or Ferrostatin-1 (Fer-1), and in BSO-treated zebrafish. 88 Another camphor-based probe CBO (26) exhibited a turn-on fluorescence response to Fe(II) incubated onion cells and zebrafish.…”

“…In its simplest iteration, a small-molecule fluorescent metal sensor comprises two domains: the fluorophore and the metal-responsive recognition domain. Fluorophores generally require visible excitation and emission wavelengths to avoid cellular autofluorescence and phototoxicity, with more recent interest in near-infrared fluorophores that can enable deeper tissue penetration for in vivo imaging . Commonly used fluorophore scaffolds include coumarin, 1,8-naphthalimide, fluorescein, rhodamine, cyanine, and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY).…”