title: Through-bond energy transfer-based ratiometric two-photon probe for fluorescent imaging of Pd(2+) ions in living cells and tissues.
abstract: Palladium can cause severe skin and eye irritation once it enters the human body. Ratiometric two-photon fluorescent probes can both eliminate interference from environmental factors and realize deep-tissue imaging with improved spatial localization. To quantitatively track Pd(2+) in biosystems, we report here a colorimetric and two-photon ratiometric fluorescent probe, termed Np-Rh-Pd, which consists of a two-photon fluorophore (naphthalene derivative with a D-π-A structure) and a rhodamine B dye. The two fluorophores are directly linked to form a two-photon ratiometric fluorescent probe for Pd(2+) based on a through-bond energy transfer (TBET) strategy. It exhibits highly efficient energy transfer (90%) with two well-resolved emission peaks (wavelength difference of 100 nm), which could efficiently diminish the cross talk between channels and is especially favorable for ratiometric bioimaging applications. A signal-to-background ratio of 31.2 was observed for the probe, which affords a high sensitivity for Pd(2+) with a detection limit of 2.3 × 10(-7) M. It was also found that acidity does not affect the fluorescent response of the probe to Pd(2+), which is favorable for its applications in practical samples. The probe was further used for fluorescence imaging of Pd(2+) ions in live cells and tissue slices under two-photon excitation, which showed significant tissue-imaging depths (90-270 μm) and a high resolution for ratiometric imaging.
authors: Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors: Liyi
authors: L
authors: Zhou
authors: Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors: Qianqian
authors: Q
authors: Wang
authors: Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors: Xiao-Bing
authors: XB
authors: Zhang
authors: Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors: Weihong
authors: W
authors: Tan
mesh_terms: D000818:Animals; D002470:Cell Survival; D004735:Energy Transfer; D005456:Fluorescent Dyes / Q000032:analysis* / Q000138:chemical synthesis / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D007477:Ions / Q000032:analysis; D008099:Liver / Q000737:chemistry*; D051379:Mice; D008819:Mice, Nude; D057054:Molecular Imaging / Q000379:methods*; D015394:Molecular Structure; D010165:Palladium / Q000032:analysis*; D017785:Photons
chemical_list: D005456:Fluorescent Dyes; D007477:Ions; D010165:Palladium