Photophysics Group, Department of Physics, SUPA, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow, G4 0NG, United Kingdom.
Methods Appl Fluoresc. 2018 Jul 2;6(3):035017. doi: 10.1088/2050-6120/aacdee.
Fluorescent protein-encapsulated gold nanoclusters (AuNCs) offer a non-toxic means of sensing and imaging biological phenomena on the nanoscale. However, the biofunctionality of proteins encapsulating AuNCs has not been fully elucidated to date. Here we studied the biofunctionality of the second major drug binding site (Sudlow II) of Human Serum Albumin (HSA) encapsulated AuNCs after AuNC synthesis. L-Dopa, a fluorescent drug molecule associated with the clinical treatment of Parkinson's disease, which commonly binds to the Sudlow II site, was used to study the availability of the site before and after AuNC synthesis through changes to its fluorescence characteristics. L-Dopa was observed using its intrinsic fluorescence to readily bind to HSA-AuNCs complexes. Interestingly, the fluorescence emission intensity of AuNCs linearly increased with L-Dopa concentration while exciting the AuNC directly at 470 nm, Using a 400 nM HSA-AuNC solution, L-Dopa was rapidly detected at a limit of 300 pM, indicating that HSA-AuNCs fluorescence is extremely sensitive to molecular binding at the Sudlow II binding site. Future research may be able to utilize this sensitivity to improve the fluorescence characteristics of AuNCs within HSA-AuNCs for imaging and sensing including drug binding studies.
荧光蛋白包裹的金纳米簇（AuNCs）为在纳米尺度上感应和成像生物现象提供了一种无毒的手段。然而，到目前为止，还没有充分阐明包裹 AuNCs 的蛋白质的生物功能。在这里，我们研究了 AuNC 合成后人血清白蛋白（HSA）包裹的 AuNCs 中第二个主要药物结合位点（Sudlow II）的生物功能。L-多巴是一种与帕金森病临床治疗相关的荧光药物分子，通常与 Sudlow II 位点结合，通过其荧光特性的变化来研究该位点在 AuNC 合成前后的可用性。L-多巴使用其固有荧光很容易与 HSA-AuNC 复合物结合。有趣的是，当直接在 470nm 处激发 AuNC 时，AuNCs 的荧光发射强度随 L-多巴浓度呈线性增加。使用 400nM 的 HSA-AuNC 溶液，可以快速检测到 300pM 的 L-多巴，表明 HSA-AuNCs 荧光对 Sudlow II 结合位点的分子结合极其敏感。未来的研究可能能够利用这种敏感性来改善 HSA-AuNCs 内 AuNCs 的荧光特性，用于成像和传感，包括药物结合研究。
