A Water-Soluble Conjugated Polymer with Pendant Disulfide Linkages to PEG Chains: A Highly Efficient Ratiometric Probe with Solubility-Induced Fluorescence Conversion for Thiol Detection
A Water-Soluble Conjugated Polymer with Pendant Disulfide Linkages to PEG Chains: A Highly Efficient Ratiometric Probe with Solubility-Induced Fluorescence Conversion for Thiol Detection
复制标题
一种带有 PEG 链侧链二硫键的水溶性共轭聚合物：一种用于硫醇检测的具有溶解度诱导荧光转换的高效比例探针
DOI：
10.1021/ma5021775
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发表时间：
2015-02-24
期刊：
影响因子：
5.5
通讯作者：
Huang, Wei
中科院分区：
文献类型：
--
作者：
Li, Jie;Tian, Congcong;Huang, Wei
我们研究了一种水溶性的共轭聚合物（WSCP）与侧二硫键的聚（乙二醇）（PEG）链，这是一个高效的比率探针与溶解度诱导的荧光转换硫醇检测。该WSCP掺杂有低带隙荧光团，1，4-二噻吩基苯并噻二唑（DBT），并通过二硫键用PEG修饰以增加其水溶性。由于DBT的掺杂比例较低，游离探针在水溶液中具有良好的溶解性（28 mg/mL），并显示紫色荧光。通过二硫键的裂解诱导的水溶性PEG链与缀合骨架的分离将导致探针的水溶性显著降低。扫描电子显微镜、动态光散射和荧光分光光度计的结合使用进一步证实，溶解度降低产生疏水缀合主链的聚集，随后增加从缀合主链到DBT的荧光共振能量转移效率，其表现为从紫色到红色的荧光转换。探针的荧光比率（I-628/I-420）从最低值0.095变化到1.15（最大增强12倍）。检测限为2.56 μ g/mL（0.021 mM）。通过对多种生物分子的检测，证实了WSCP探针是一种对巯基具有高选择性的良好传感材料。我们还成功地实现了HeLa细胞内巯基的成像。考虑到二硫键可以被其他可裂解的连接所取代，这种由溶解度降低诱导的荧光比率法可以用于检测其他链可裂解的生物分子，这将有助于开发基于缀合聚合物的新探针。
We investigated a water-soluble conjugated polymer (WSCP) with pendant disulfide linkages to poly(ethylene glycol) (PEG) chains, which is a highly efficient ratiometric probe with solubility-induced fluorescence conversion for thiol detection. This WSCP was doped with a low-bandgap fluorophore, 1,4-dithienyl benzothiadiazole (DBT), and was modified with PEGs by disulfide linkages to increase its water solubility. The free probe exhibited good solubility in aqueous solution (28 mg/mL) and showed purple fluorescence because of the low doping ratio of DBT. The separation of water-soluble PEG chains from the conjugated backbone induced by the cleavage of the disulfide linkages would lead to a significant decrease of the water solubility of the probe. The combined utilization of scanning electron microscopy, dynamic light scattering, and fluorescence spectrophotometer further confirmed that decreased solubility produced an aggregation of the hydrophobic conjugated backbone and subsequently increased fluorescence resonance energy transfer efficiency from the conjugated backbone to DBT which manifested as fluorescence conversion from purple to red. The fluorescence ratiometry (I-628/I-420) of the probe varied from the lowest value of 0.095 to 1.15 (12-fold maximum enhancement). The detection limit was 2.56 mu g/mL (0.021 mM). The WSCP probe was confirmed to be a good sensing material with high selectivity for thiols by examining various biological molecules. We also successfully achieved the imaging of intracellular thiols in HeLa cell. Considering that the disulfide could be replaced by other cleavable linkages, such a fluorescence ratiometry induced by decreased solubility could be utilized for detecting other chain-cleavable biomolecules, which would contribute to the development of new probes based on conjugated polymers.