title: Single- and multiphoton turn-on fluorescent Fe(3+) sensors based on bis(rhodamine).
abstract: Selective and sensitive turn-on fluorescent Fe(3+) sensors based on novel bis(rhodamine) dye molecules are reported. The compounds are synthesized with very high yields and characterized with NMR, ESI mass spectrometry, and elemental analysis. Single- and two-photon fluorescence enhancement is observed for both molecules in the presence of Fe(3+). High selectivity and sensitivity is observed over other metal ions and is shown to be due mainly to the spirolactam ring-opening power of Fe(3+). All measurements are made in buffer environments simulating biological conditions to facilitate single- and multiphoton fluorescence imaging of Fe(3+) in vivo and in vitro. Larger enhancement of fluorescence for both one- and two-photon excitation makes them suitable candidates for fluorescent labeling of biological systems. Two photon cross-section and time-resolved fluorescence measurements are utilized to understand the selectivity of the present sensors for Fe(3+)-sensing.
authors.affiliation: Department of Chemistry, Western Michigan University, Kalamazoo Michigan 49008, USA.
authors.forename: Aruna J
authors.initials: AJ
authors.lastname: Weerasinghe
authors.forename: Carla
authors.initials: C
authors.lastname: Schmiesing
authors.forename: Shankar
authors.initials: S
authors.lastname: Varaganti
authors.forename: Guda
authors.initials: G
authors.lastname: Ramakrishna
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Sinn
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D017785:Photons; D012235:Rhodamines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; D012235:Rhodamines; D007501:Iron