State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering , Hunan University , Changsha 410082 , China.
Department of Laboratory Medicine, Nanfang Hospital , Southern Medical University , Guangzhou 510515 , China.
ACS Appl Mater Interfaces. 2019 Aug 21;11(33):29619-29629. doi: 10.1021/acsami.9b10359. Epub 2019 Aug 7.
The analysis of albumin has clinical significance in diagnostic tests and obvious value to research studies on the albumin-mediated drug delivery and therapeutics. The present immunoassay, instrumental techniques, and colorimetric methods for albumin detection are either expensive, troublesome, or insensitive. Herein, a class of water-soluble tetrazolate-functionalized derivatives with aggregation-induced emission (AIE) characteristics is introduced as novel fluorescent probes for albumin detection. They can be selectively lighted up by site-specific binding with albumin. The resulting albumin fluorescent assay exhibits a low detection limit (0.21 nM), high robustness in aqueous buffer (pH = 6-9), and a broad tunable linear dynamic range (0.02-3000 mg/L) for quantification. The tetrazolate functionality endows the probes with a superior water solubility (>0.01 M) and a high binding affinity to albumin ( = 0.25 μM). To explore the detection mechanism, three unique polar binding sites on albumin are computationally identified, where the multivalent tetrazolate-lysine interactions contribute to the tight binding and restriction of the molecular motion of the AIE probes. The key role of lysine residues is verified by the detection of poly-l-lysine. Moreover, we applied the fluorogenic method to quantify urinary albumin in clinical samples and found it a feasible and practical strategy for albumin analysis in complex biological fluids.
白蛋白分析在诊断测试中具有临床意义，对白蛋白介导的药物输送和治疗学的研究具有明显的价值。目前用于检测白蛋白的免疫分析、仪器技术和比色法要么昂贵、麻烦，要么不灵敏。在此，我们引入了一类具有聚集诱导发射（AIE）特性的水溶性四唑基功能化衍生物，作为用于白蛋白检测的新型荧光探针。它们可以通过与白蛋白的特异性结合被选择性点亮。由此产生的白蛋白荧光测定法具有低检测限（0.21 nM）、在水缓冲液（pH = 6-9）中高稳健性和用于定量的宽可调线性动态范围（0.02-3000 mg/L）。四唑基赋予探针优异的水溶性（>0.01 M）和与白蛋白的高结合亲和力（= 0.25 μM）。为了探索检测机制，我们通过计算鉴定出白蛋白上三个独特的极性结合位点，其中多价四唑-赖氨酸相互作用有助于 AIE 探针的紧密结合和分子运动的限制。赖氨酸残基的关键作用通过对多聚赖氨酸的检测得到了验证。此外，我们还将荧光法应用于临床样本中尿白蛋白的定量，发现这是一种在复杂生物体液中分析白蛋白的可行且实用的策略。
