title: Naphthalimide-porphyrin hybrid based ratiometric bioimaging probe for Hg2+: well-resolved emission spectra and unique specificity.
abstract: In this paper, we unveil a novel naphthalimide-porphyrin hybrid based fluorescence probe (1) for ratiometric detection of Hg(2+) in aqueous solution and living cells. The ratiometric signal change of the probe is based on a carefully predesigned molecule containing two independent Hg(2+)-sensitive fluorophores with their maximal excitation wavelengths located at the same range, which shows reversibly specific ratiometric fluorescence responses induced by Hg(2+). In the new developed sensing system, the emissions of the two fluorophores are well-resolved with a 125 nm difference between two emission maxima, which can avoid the emission spectra overlap problem generally met by spectra-shift type probes and is especially favorable for ratiometric imaging intracellular Hg(2+). It also benefits from a large range of emission ratios and thereby a high sensitivity for Hg(2+) detection. Under optimized experimental conditions, the probe exhibits a stable response for Hg(2+) over a concentration range from 1.0 x 10(-7) to 5.0 x 10(-5) M, with a detection limit of 2.0 x 10(-8) M. The response of the probe toward Hg(2+) is reversible and fast (response time less than 2 min). Most importantly, the ratiometric fluorescence changes of the probe are remarkably specific for Hg(2+) in the presence of other abundant cellular metal ions (i.e., Na(+), K(+), Mg(2+), and Ca(2+)), essential transition metal ions in cells (such as Zn(2+), Fe(3+), Fe(2+), Cu(2+), Mn(2+), Co(2+), and Ni(2+)), and environmentally relevant heavy metal ions (Ag(+), Pb(2+), Cr(3+), and Cd(2+)), which meets the selective requirements for biomedical and environmental monitoring application. The recovery test of Hg(2+) in real water samples demonstrates the feasibility of the designed sensing system for Hg(2+) assay in practical samples. It has also been used for ratiometric imaging of Hg(2+) in living cells with satisfying resolution, which indicates that our novel designed probe has effectively avoided the general emission spectra overlap problem of other ratiometric probes.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Li
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Qiao
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: He
authors.forename: Shuang-Yan
authors.initials: SY
authors.lastname: Huan
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Lu
authors.forename: Li-Xin
authors.initials: LX
authors.lastname: Jian
authors.forename: Guo-Li
authors.initials: GL
authors.lastname: Shen
authors.forename: Ru-Qin
authors.initials: RQ
authors.lastname: Yu
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D008628:Mercury / Q000032:analysis*; D008856:Microscopy, Fluorescence; D053644:Naphthalimides / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005456:Fluorescent Dyes; D053644:Naphthalimides; D011166:Porphyrins; D008628:Mercury