A key hurdle toward effective application of nanoparticles (NPs) in biomedicine is still the incomplete understanding of the biomolecular adsorption layer, the so-called protein corona, which inevitably forms around NPs when they are immersed in a biofluid. NP sizing techniques via the analysis of Brownian motions offer a powerful way to measure the thickness of the protein corona in situ. Here, the fundamentals of three techniques, dynamic light scattering, fluorescence correlation spectroscopy, and nanoparticle tracking analysis are briefly summarized. Then, experimental procedures for the determination of binding curves are presented in a tutorial fashion. Nanoparticle sizing experiments are illustrated with a selection of recent results on the interactions of transferrin with hydrophilic and hydrophobic polystyrene nanoparticles, and key insights gained from this work are discussed.

中文翻译：

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基于布朗运动的纳米颗粒大小——一种用于纳米颗粒-蛋白质相互作用原位分析的强大方法

纳米粒子 (NPs) 在生物医学中有效应用的一个关键障碍仍然是对生物分子吸附层的不完全了解，即所谓的蛋白质电晕，当它们浸入生物流体时不可避免地会在 NPs 周围形成。通过布朗运动分析的 NP 尺寸技术提供了一种强大的方法来原位测量蛋白质电晕的厚度. 在这里，简要总结了动态光散射、荧光相关光谱和纳米粒子跟踪分析这三种技术的基本原理。然后，以教程的方式介绍了确定结合曲线的实验程序。纳米颗粒大小实验通过一系列关于转铁蛋白与亲水性和疏水性聚苯乙烯纳米颗粒相互作用的最新结果进行说明，并讨论了从这项工作中获得的关键见解。