Department of Physical Sciences, Arkansas Tech University, Russellville, AR 72801, United States.
Department of Physical Sciences, Arkansas Tech University, Russellville, AR 72801, United States.
Spectrochim Acta A Mol Biomol Spectrosc. 2020 Jul 5;235:118305. doi: 10.1016/j.saa.2020.118305. Epub 2020 Mar 24.
In diagnostic medicine serum albumin is considered as an important biomarker for assessment of cardiovascular functions and diagnosis of renal diseases. Herein, we report a novel donor-π-π-acceptor fluorophore for selective detection of serum albumin in urine samples. In our design, a phenolic donor was conjugated with a tricyanofuran (TCF) acceptor through a dimethine bridge via a simple condensation reaction. The stereoelectronic effects of the incorporated methoxy (-OCH) groups and the TCF moiety-in conjunction with the extended π-electron conjugation-led to dual red and NIR-I absorption/emission in water. Moreover, due to superior electron transfer between a phenolate donor and the TCF acceptor and the subsequent energy decay from the charge transfer states, the fluorophore displayed negligible fluorescence emission in water and other polar solvents. Consequently, we have been able to utilize the fluorophore for quantitative estimation of serum albumin both in the red (<700 nm) and NIR-I (700-900 nm) regions of the electromagnetic spectrum with excellent reproducibility. The fluorophore selectively recognized human serum albumin over other proteins and enzymes with a limit of detection of 10 mg/L and 20 mg/L in simulated urine samples at red and NIR-I emission window of the spectrum, respectively. By molecular docking analysis and experimental displacement assays, we have shown that the selective response of the fluorophore toward human serum albumin is due to tighter supramolecular complexation between the fluorophore and the protein at subdomain IB, and the origin of the NIR-I (780 nm) emission was attributed to a twisted conformer of phenolate-π-π-TCF system in aqueous solution. These findings indicate that the fluorophore could be utilized for quantitative detection of human serum albumin in urine samples for clinical diagnosis of albuminuria.
在诊断医学中，血清白蛋白被认为是评估心血管功能和诊断肾脏疾病的重要生物标志物。在此，我们报告了一种用于选择性检测尿液样品中血清白蛋白的新型供体-π-π-受体荧光团。在我们的设计中，通过简单的缩合反应，将酚供体通过亚甲桥与三氰呋喃（TCF）受体共轭。所包含的甲氧基（-OCH 3 ）基团和 TCF 部分的立体电子效应-结合扩展的π-电子共轭-导致在水中具有双重红色和近红外-I 吸收/发射。此外，由于酚盐供体和 TCF 受体之间的优异电子转移以及随后从电荷转移态的能量衰减，荧光团在水中和其他极性溶剂中几乎没有荧光发射。因此，我们能够利用该荧光团在电磁光谱的红色（<700nm）和近红外-I（700-900nm）区域对血清白蛋白进行定量估计，具有出色的重现性。该荧光团选择性地识别人血清白蛋白，超过其他蛋白质和酶，在红色和近红外-I 发射窗口的模拟尿液样品中，检测限分别为 10mg/L 和 20mg/L。通过分子对接分析和实验置换测定，我们表明，荧光团对人血清白蛋白的选择性响应是由于在亚结构域 IB 处荧光团与蛋白质之间的超分子络合更紧密，而近红外-I（780nm）发射的起源归因于在水溶液中酚盐-π-π-TCF 体系的扭曲构象。这些发现表明，该荧光团可用于定量检测尿液样品中的人血清白蛋白，用于临床诊断白蛋白尿。
