Chair of Medical Biochemistry, Jagiellonian University Medical College, Kopernika, Kraków, Poland.
Eur Biophys J. 2011 Oct;40(10):1187-96. doi: 10.1007/s00249-011-0750-z. Epub 2011 Sep 24.
Among specific amyloid ligands, Congo red and its analogues are often considered potential therapeutic compounds. However, the results of the studies so far have not been univocal because the properties of this dye, derived mostly from its supramolecular nature, are still poorly understood. The supramolecular structure of Congo red, formed by π-π stacking of dye molecules, is susceptible to the influence of the electric field, which may significantly facilitate electron delocalization. Consequently, the electric field may generate altered physico-chemical properties of the dye. Enhanced electron delocalization, induced by the electric field, alters the total charge of Congo red, making the dye more acidic (negatively charged). This is a consequence of withdrawing electrons from polar substituents of aromatic rings-sulfonic and amino groups-thus increasing their tendency to dissociate protons. The electric field-induced charge alteration observed in electrophoresis depends on dye concentration. This concentration-dependent charge alteration effect disappears when the supramolecular structure disintegrates in DMSO. Dipoles formed from supramolecular fibrillar species in the electric field become ordered in the solution, introducing the modified arrangement to liquid crystalline phase. Experimental results and theoretical studies provide evidence confirming predictions that the supramolecular character of Congo red is the main reason for its specific properties and reactivity.
在特定的淀粉样蛋白配体中，刚果红及其类似物通常被认为是有潜力的治疗化合物。然而，到目前为止，研究结果并不一致，因为这种染料的性质主要源于其超分子性质，而这些性质仍未被充分理解。刚果红的超分子结构由染料分子的π-π堆积形成，容易受到电场的影响，这可能会显著促进电子离域。因此，电场可能会产生染料物理化学性质的改变。电场诱导的电子离域增强，改变了刚果红的总电荷，使染料更具酸性（带负电荷）。这是因为从芳香环的极性取代基（磺酸基和氨基）中夺取电子，从而增加了它们离解质子的倾向。电泳中观察到的电场诱导的电荷变化取决于染料的浓度。当超分子结构在 DMSO 中解体时，这种浓度依赖性的电荷变化效应消失。在电场中形成的超分子纤维状物质的偶极子在溶液中有序排列，将修饰后的排列引入液晶相。实验结果和理论研究提供了证据，证实了刚果红的超分子性质是其特定性质和反应性的主要原因的预测。
