水溶性染料修饰的聚邻苯二胺的光谱和生物物理相互作用研究及其在 BSA 检测和生物成像中的潜在应用。
Spectroscopic and Biophysical Interaction Studies of Water-soluble Dye modified poly(o-phenylenediamine) for its Potential Application in BSA Detection and Bioimaging.
机构信息
Materials Research Laboratory Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025, India.
Advanced Instrumentation Research Facility, Jawaharlal Nehru University, New Delhi, 110067, India.
出版信息
Sci Rep. 2019 Jun 12;9(1):8544. doi: 10.1038/s41598-019-44910-z.
Ultrasound-assisted synthesis of water soluble poly(o-phenylenediamine) (POPD) and its doping with Acid Orange (AO), Fluorescein (Fluo) and Rhodamine-6G (R6G) dyes was carried out with a view to enhance the photophysical properties of POPD. XPS studies confirmed that doping of POPD occured through hydrogen bonding between NH group of POPD and C=O/SO, S=O groups of the dyes. The presence of strong hydrogen bonding was also confirmed via UV-vis studies by the addition of urea and sodium chloride to the dye modified POPD adducts. Molar extinction coefficient of these adducts was found to bear a close relationship with the molecular structure. Fluorescence life time, (τ) was found to be lowest (1.8 ns) for AO-POPD and highest (3.2 ns) for Fluo-POPD. The structure of AO-POPD was more strained, while that of Fluo-POPD was least strained. Intrinsic fluorescence decay constant, (k) showed increasing values for POPD, AO-POPD, Fluo-POPD, R6G-POPD as 0.071, 0.072, 0.153, and 0.172 (10 s), which could be correlated to the increasing strain-free molecular structure of the adducts. Circular dichroism spectra (CD) of BSA in presence of POPD and R6G- POPD revealed that it partially broke its helical structure, while Fluo-POPD and AO-POPD showed enhancement in the helical content. The 3-D fluorescence studies confirmed enhancement in hydrophobicity of POPD and R6G- POPD and increase in hydrophylicity of AO-POP and Fluo-POPD in the microenvironment of tryptophan residue-213 of BSA. Fluo-POPD and R6G-POPD adducts were chosen to find out the lowest detection limit (LOD) of BSA by differential pulse voltammetry (DPV) which was found to be 1.35 nM, and 1.65 nM using Fluo-POPD and R6G -POPD respectively. The binding constant of BSA with Fluo-POPD- and R6G-POPD was obtained as 3.98 × 10 Lmol and 5.27 × 10 Lmol. These polymers could therefore, be used for the detection of BSA. Live cell imaging revealed that POPD nanoparticles were bound to the outer membrane of E. coli, while R6G-POPD, showed penetration into the cytoplasm and excellent labeling of E. coli. This facile technique could be used to design tunable biomarkers by tailoring the conjugated polymer with a desired dye molecule.
超声辅助合成水溶性聚邻苯二胺（POPD），并将其与酸性橙（AO）、荧光素（Fluo）和罗丹明 6G（R6G）染料掺杂，以增强 POPD 的光物理性质。XPS 研究证实，POPD 的掺杂是通过 POPD 的 NH 基团与染料的 C=O/SO、S=O 基团之间的氢键发生的。通过向染料修饰的 POPD 加合物中添加尿素和氯化钠，通过 UV-vis 研究也证实了存在强氢键。这些加合物的摩尔消光系数与分子结构密切相关。发现这些加合物的荧光寿命（τ）对于 AO-POPD 最低（1.8 ns），对于 Fluo-POPD 最高（3.2 ns）。AO-POPD 的结构更紧张，而 Fluo-POPD 的结构最不紧张。固有荧光衰减常数（k）对于 POPD、AO-POPD、Fluo-POPD、R6G-POPD 分别显示出增加的值 0.071、0.072、0.153 和 0.172（10 s），这可以与加合物中不断增加的无应变分子结构相关联。BSA 存在时 POPD 和 R6G-POPD 的圆二色性（CD）光谱表明，它部分破坏了其螺旋结构，而 Fluo-POPD 和 AO-POPD 显示出螺旋含量增加。3-D 荧光研究证实，POPD 和 R6G-POPD 的疏水性增强，BSA 色氨酸残基 213 微环境中 AO-POP 和 Fluo-POPD 的亲水性增加。选择 Fluo-POPD 和 R6G-POPD 加合物通过差分脉冲伏安法（DPV）来确定 BSA 的最低检测限（LOD），发现使用 Fluo-POPD 和 R6G-POPD 时，BSA 的 LOD 分别为 1.35 nM 和 1.65 nM。BSA 与 Fluo-POPD 和 R6G-POPD 的结合常数分别为 3.98×10^3 Lmol 和 5.27×10^3 Lmol。因此，这些聚合物可用于检测 BSA。活细胞成像显示，POPD 纳米颗粒与大肠杆菌的外膜结合，而 R6G-POPD 则进入细胞质并对大肠杆菌进行了出色的标记。这种简单的技术可以通过用所需的染料分子修饰共轭聚合物来设计可调谐的生物标志物。
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