一种基于分子内质子转移发色团的硫化氢荧光探针的合成及其生物成像研究

Synthesis of a Fluorescent Probe for HS Detection Based on an Excited-state Intramolecular Proton Transfer Fluorophore and Its Applications in Biological Imaging

硫化氢在许多生理过程中扮演十分重要的角色,因此检测和成像生物体内的硫化氢具有十分重要的意义。该研究成功制备了一种基于分子内质子转移发色团的硫化氢荧光探针(DHCD)。在PBS-DMSO(磷酸盐-二甲基亚砜,99∶1,体积比,pH 7.45)缓冲溶液中,DHCD的荧光强度与NaHS的浓度在0~10μmol/L范围内呈现良好的线性关系,检出限为0.84μmol/L。该探针对硫化氢的响应具有较大的Stokes位移(~165 nm)、高灵敏度和选择性。此外,合成的探针拥有良好的细胞渗透性和低的毒性,可用于HeLa细胞中硫化氢的荧光成像,在生物分析中具有潜在应用价值。

It is very meaningful for the detection and imaging of H2S in living systems due to its important role in many biological processes.In this work,a novel fluorescent probe,DHCD was designed and synthesized for the detection of H2S based on an excited-state intramolecular proton transfer(ESIPT) fluorophore.The free probe showed relatively weak fluorescence as the protection of the OH group on a 2,4-dinitrophenyl group in the fluorophore blocked the ESIPT process.However,in presence of H2S,the sensing system displayed a remarkable fluorescence enhancement accompanying with a large Stokes shift(~165 nm) due to the recovery of the ESIPT process resulting from the thiolysis of the 2,4-dinitrophenyl ether in probe DHCD triggered by HS-.The detecting mechanism of probe DHCD for H2S was confirmed by high resolution mass spectrometry.In PBS-DMSO buffer(pH 7.45,99 ∶1,by volume),the normalized fluorescence intensity increased linearly with the concentration of HS- within the range of 0-10 μmol/L,and the detection limit of the probe DHCD for HS- was calculated to be 0.84 μmol/L.In addition,the synthesized probe had not only a high selectivity to H2S other than other biologically related analytes,but also a high anti-interference ability against other coexisting species,which could satisfy the requirements for the selective detection of H2S in real samples from different origins.Most importantly,this probe possessed excellent cell permeation and low toxicity,and could be used for fluorescent imaging of H2S in HeLa cells.It thus provides a promising approach for studying the effects of H2S in biological systems,and exhibits a great potential in biological applications.