Obstarczyk Patryk, Pniakowska Anna, Grzelczak Marcin P, Olesiak-Bańska Joanna
Institute of Advanced Materials, Wroclaw University of Science and Technology, 50-370 Wrocław, Poland.
Faculty of Engineering and Natural Sciences, Tampere University, FI-33720 Tampere, Finland.
ACS Omega. 2023 Mar 13;8(12):11503-11511. doi: 10.1021/acsomega.3c00426. eCollection 2023 Mar 28.
The distinct polarity of biomolecule surfaces plays a pivotal role in their biochemistry and functions as it is involved in numerous processes, such as folding, aggregation, or denaturation. Therefore, there is a need to image both hydrophilic and hydrophobic bio-interfaces with markers of distinct responses to hydrophobic and hydrophilic environments. In this work, we present a synthesis, characterization, and application of ultrasmall gold nanoclusters capped with a 12-crown-4 ligand. The nanoclusters present an amphiphilic character and can be successfully transferred between aqueous and organic solvents and have their physicochemical integrity retained. They can serve as probes for multimodal bioimaging with light (as they emit near-infrared luminescence) and electron microscopy (due to the high electron density of gold). In this work, we used protein superstructures, namely, amyloid spherulites, as a hydrophobic surface model and individual amyloid fibrils with a mixed hydrophobicity profile. Our nanoclusters spontaneously stained densely packed amyloid spherulites as observed under fluorescence microscopy, which is limited for hydrophilic markers. Moreover, our clusters revealed structural features of individual amyloid fibrils at a nanoscale as observed under a transmission electron microscope. We show the potential of crown ether-capped gold nanoclusters in multimodal structural characterization of bio-interfaces where the amphiphilic character of the supramolecular ligand is required.
生物分子表面独特的极性在其生物化学和功能中起着关键作用，因为它参与了许多过程，如折叠、聚集或变性。因此，需要用对疏水和亲水环境有不同响应的标记物来成像亲水性和疏水性生物界面。在这项工作中，我们展示了一种用12-冠-4配体封端的超小金纳米团簇的合成、表征及应用。这些纳米团簇具有两亲性，能够在水相和有机溶剂之间成功转移，并保持其物理化学完整性。它们可以用作多模态生物成像的探针，用于光学成像（因为它们发射近红外发光）和电子显微镜成像（由于金的高电子密度）。在这项工作中，我们使用蛋白质超结构，即淀粉样球晶，作为疏水表面模型，以及具有混合疏水特性的单个淀粉样纤维。我们的纳米团簇在荧光显微镜下观察到能自发地密集染色堆积的淀粉样球晶，而亲水性标记物在这方面受限。此外，在透射电子显微镜下观察到，我们的团簇揭示了单个淀粉样纤维在纳米尺度上的结构特征。我们展示了冠醚封端的金纳米团簇在生物界面多模态结构表征中的潜力，其中需要超分子配体的两亲性。
