用于细胞成像的双氰基二苯代乙烯衍生物双光子荧光银离子探针

A Dicyanostilbene-Derived Two-Photon Fluorescence Probe for Free Silver Ions Used in Cell-Imaging

双光子荧光显微成像兼具诸如近红外激发、暗场成像、避免荧光漂白和光致毒、定靶激发、高横向分辨率与纵向分辨率、降低生物组织吸光系数及降低组织自发荧光干扰等特点,显著地优于单光子荧光显微成像,为生命科学研究提供了更为便利的工具。因此双光子荧光探针适合于生物检测与成像。制备了衍生于二苯代乙烯的双光子荧光银离子探针,此探针以拥有异常大的双光子吸收截面(δTPA)的4-甲基-2,5-二氰基-4'-氨基二苯乙烯(DCS)作为双光子荧光母体,以6-芳基-3,9-二硫-6-氮杂癸烷(TAU)为Ag+配体。探针显示了大的δTPA(在Me CN中,950 GM)、对银离子有高的灵敏性与选择性、强的双光子荧光(790 nm激光激发时)。探针的络合常数为lg K=5.76±0.05。探针能选择性地检测和成像活细胞中的游离Ag+,可用于细胞中微量Ag+的分析检测与成像。此探针为开发理想的双光子荧光探针提供了可供借鉴的平台。

Two-photon fluorescence imaging with such properties as NIR（ near infrared） photons excitation source,fixed target excitation,high transverse and lognitudinal resolutions,etc. is superior to one-photon fluorescence imaging,and become powerful tools for the study on life science. Therefore,the two-photon fluorescence sensors are suitable for bioassay and bioimaging. A novel dicyanostibene-derived two-photon fluorescence probe for Ag^＋was prepared by using 4-methyl-2,5-dicyano-4＇-amino stilbene（ DCS） with a remarkably large the two-photon absorption cross section（ δTPA） as a two-photon fluorophore and 6-aryl-3,9-dithia-6-azaundecane（ TAU） as a novel Ag^＋ligand. The sensor exhibits remarkably large δTPAwhose value is as high as 950 GM in Me CN,high sensitivity to and selectivity for silver ion,and emits strong two-photon fluorescence when excited by 790 nm laser photons. The sensor can be used to detect trace Ag^＋,and its binding constant（ lg K） for Ag^＋is as high as 5. 76 ± 0. 05. The sensor can selectively detect and image free Ag^＋in live cells. The successful applications of the sensor provide a brilliant prototype for the development of ideal two-photon fluorescence probes.