College of Chemistry, Beijing Normal University, Beijing 100875, China.
Chemistry. 2012 Jan 27;18(5):1438-43. doi: 10.1002/chem.201102187. Epub 2012 Jan 16.
Novel amine-terminated silicon (Si) quantum dots (QDs) were synthesized and applied for the detection of human serum proteins on gels directly after polyacrylamide gel electrophoresis (PAGE). The diameter of these stable amine-terminated Si QDs was in the range of 0.5-2.0 nm. In this study, the fluorescent imaging conditions, such as the buffer solution, pH value, buffer concentration and quantity of Si QDs, were optimized and the possible mechanisms of Si QDs-protein interaction were analyzed. The mode of Si QDs and human serum albumin association was found to occur by hydrogen bond interactions; this was probably attributed to the interaction between the amino group of amine-terminated Si QDs and the carboxyl group of proteins. Meanwhile, human serum proteins separated by native 1D and native 2D electrophoresis were detected by Si QD-based fluorescent imaging. Some proteins, such as isoform 1 of α-1-antitrypsin, complement C3 (Fragment) and hemopexin, which were identified by mass spectrometry (MS), were easily detected by using Si QDs, but not with CBB-R250 staining. The Si QDs-based fluorescent imaging technique with high resolution is a sensitive and dependable method for direct detection of human serum proteins, and has enormous potential in clinical diagnosis.
新型胺基封端硅（Si）量子点（QD）被合成出来，并在聚丙烯酰胺凝胶电泳（PAGE）后直接用于凝胶中人体血清蛋白的检测。这些稳定的胺基封端 Si QD 的直径在 0.5-2.0nm 范围内。在本研究中，优化了荧光成像条件，如缓冲溶液、pH 值、缓冲液浓度和 Si QD 的用量，并分析了 Si QD-蛋白相互作用的可能机制。Si QD 与人血清白蛋白结合的模式是通过氢键相互作用发生的；这可能归因于胺基封端 Si QD 的氨基与蛋白质的羧基之间的相互作用。同时，基于 Si QD 的荧光成像检测到了通过天然 1D 和天然 2D 电泳分离的人体血清蛋白。一些通过质谱（MS）鉴定的蛋白质，如α-1-抗胰蛋白酶同工酶 1 型、补体 C3（片段）和血红素结合蛋白，很容易通过 Si QD 检测到，但用 CBB-R250 染色则检测不到。高分辨率的 Si QD 荧光成像技术是一种灵敏、可靠的直接检测人体血清蛋白的方法，在临床诊断中具有巨大的潜力。
