双氰基二苯代乙烯型双光子荧光铅离子探针

Dicyanostilbene-derived Two-photon Fluorescence Probe for Lead Ions

以4-甲基-2,5-二氰基-4'-氨基二苯代乙烯(DCS)和双[2-(2-氨基苯基硫基)乙基]胺(BSA)分别作为双光子荧光团和铅离子配体,构建了1个新型的双光子荧光Pb2+探针(DPb),并对其结构和性能进行了表征.结果表明,该探针具有分子尺寸小、双光子吸收截面大(δ_(TPA),1020 GM)、长波长发射(λmax=609 nm)、斯托克斯位移大(209 nm)、光稳定性好、水溶性适宜、细胞渗透性优良、无细胞毒性及在生理环境下对p H不依赖等优点.该探针能选择性地检测细胞与组织中的Pb2+,猝灭常数K^(TP)_(sv)=7.58×10~5L/mol.

One-photon microscopy（ OPM） uses a single photon of higher energy to excite the fluorophore,while two-photon microscopy（ TPM） uses two photons of lower energy as the excitation source. Therefore,TPM has such distinct advantages as improvement of penetration depth,localized two-photon excitation,reduction of photo-damage and photobleaching,small absorption coefficient of light in tissue,and lower tissue autofluorescence. These advantages make TPM more popular among biologists. Lead is a common contaminant and has inherent toxic effects on human health and environment. Pb2＋ion contamination can affect a wide variety of diseases such as anemia,irritability,memory loss,and muscle paralysis. For these reasons,there is an urgent need to develop some effective two-photon fluorescence probes to detect trace amounts of Pb2＋ions in live cells and tissues. A novel two-photon fluorescence probe for Pb2＋derived from 4-methyl-2,5-dicyano-4＇-amino stilbene as a two-photon fluorophore and bis[2-（ 2-aminophenylsulfanyls） ethyl]amine as a novel Pb2＋ligand was developed. The probe possessed small molecule size, large two-photon absorption cross-section（ 1020 GM）,noncytotoxic effect,long-wavelength emission at 609 nm,large Stokes shift（ 209 nm）,excellent photostability,moderate water-solubility, good cell-permeability and p H-insensitivity in the biologically relevant range. The probe was able to selectively detect Pb2＋ions in live cells and living tissues without interference from other metal ions and the membrane-bound probes,and its quenching constant（ KTPsv） was 7. 58×10 5 L/mol.