Choudhury Rajib, Paudel Pratikshya, Sharma Arun K, Webb Sydney, Ware Morgan
Department of Physical Sciences, Arkansas Tech University, Russellville, Arkansas, 72801, United States.
Department of Physical Sciences, Wagner College, Staten Island, New York, 10301, United States.
J Photochem Photobiol A Chem. 2022 Jan 1;422. doi: 10.1016/j.jphotochem.2021.113563. Epub 2021 Sep 30.
In this article a syringol-π-benz[e]indolium based donor-acceptor fluorophore has been reported. The fluorophore shows a solvent polarity dependent change in the absorption and emission spectra in solution. A combined spectroscopic and time dependent density functional theory (TDDFT) studies reveal higher dipole moment of the fluorophore in the excited state, resulting positive solvatochromism. In physiological pH, the phenol group in the fluorophore is easily deprotonated owing to the electron pulling effect of the substituents. Consequently, the phenolate (PhO-) becomes a strong active donor in the new donor-acceptor pair. In aqueous solution, the new phenolate fluorochrome shows negligible fluorescence due to energy loss via non-radiative pathways from the low-lying polar excited states. The fluorochrome can detect human and bovine serum albumins in physiological buffer solution with high selectivity. The underlying mechanism of human serum albumin (HSA) detection was estimated to be strong (1.46 × 10 M, ΔG = -7.05 kcal/mol) supramolecular complexation between the fluorophore and albumin in hydrophobic binding site III-B. The linear relationship between fluorescence intensity and HSA concentration extends from 40 mg/L to an impressive upper limit (540 mg/L), thereby opening an opportunity for albumin detection in a broad range of health conditions. The practical applicability of the fluorophore was tested in spiked urine samples and a good correlation was observed between fluorescence intensity and the concentration of human serum albumin in neutral aqueous samples.
在本文中，报道了一种基于丁香酚-π-苯并[e]吲哚鎓的供体-受体荧光团。该荧光团在溶液中的吸收光谱和发射光谱显示出与溶剂极性相关的变化。结合光谱学和含时密度泛函理论（TDDFT）研究表明，该荧光团在激发态具有更高的偶极矩，从而导致正溶剂化显色现象。在生理pH值下，由于取代基的电子吸引作用，荧光团中的酚基团很容易去质子化。因此，酚盐（PhO-）在新的供体-受体对中成为强活性供体。在水溶液中，由于来自低能极性激发态的非辐射途径导致能量损失，新的酚盐荧光染料显示出可忽略不计的荧光。该荧光染料能够在生理缓冲溶液中高选择性地检测人和牛血清白蛋白。据估计，检测人血清白蛋白（HSA）的潜在机制是荧光团与白蛋白在疏水结合位点III-B中形成强（1.46×10 M，ΔG = -7.05 kcal/mol）的超分子络合物。荧光强度与HSA浓度之间的线性关系从40 mg/L延伸到令人印象深刻的上限（540 mg/L），从而为在广泛的健康状况下检测白蛋白提供了机会。在加标的尿液样本中测试了该荧光染料的实际适用性，并且在中性水性样本中观察到荧光强度与人类血清白蛋白浓度之间具有良好的相关性。
