NanoScience Technology Center and Department of Chemistry, University of Central Florida , 12424 Research Parkway Suite 400, Orlando, Florida 32826, United States.
Nano Discovery Inc. , 3259 Progress Drive Suite 141, Orlando, Florida 32826, United States.
ACS Appl Mater Interfaces. 2016 Aug 24;8(33):21585-94. doi: 10.1021/acsami.6b06903. Epub 2016 Aug 9.
Gold nanoparticles (AuNPs) have found broad applications in chemical and biological sensing, catalysis, biomolecular imaging, in vitro diagnostics, cancer therapy, and many other areas. Dynamic light scattering (DLS) is an analytical tool used routinely for nanoparticle size measurement and analysis. Due to its relatively low cost and ease of operation in comparison to other more sophisticated techniques, DLS is the primary choice of instrumentation for analyzing the size and size distribution of nanoparticle suspensions. However, many DLS users are unfamiliar with the principles behind the DLS measurement and are unware of some of the intrinsic limitations as well as the unique capabilities of this technique. The lack of sufficient understanding of DLS often leads to inappropriate experimental design and misinterpretation of the data. In this study, we performed DLS analyses on a series of citrate-stabilized AuNPs with diameters ranging from 10 to 100 nm. Our study shows that the measured hydrodynamic diameters of the AuNPs can vary significantly with concentration and incident laser power. The scattered light intensity of the AuNPs has a nearly sixth order power law increase with diameter, and the enormous scattered light intensity of AuNPs with diameters around or exceeding 80 nm causes a substantial multiple scattering effect in conventional DLS instruments. The effect leads to significant errors in the reported average hydrodynamic diameter of the AuNPs when the measurements are analyzed in the conventional way, without accounting for the multiple scattering. We present here some useful methods to obtain the accurate hydrodynamic size of the AuNPs using DLS. We also demonstrate and explain an extremely powerful aspect of DLS-its exceptional sensitivity in detecting gold nanoparticle aggregate formation, and the use of this unique capability for chemical and biological sensing applications.
金纳米粒子（AuNPs）在化学和生物传感、催化、生物分子成像、体外诊断、癌症治疗和许多其他领域得到了广泛的应用。动态光散射（DLS）是一种常用的分析工具，用于纳米粒子尺寸测量和分析。与其他更复杂的技术相比，DLS 具有相对较低的成本和易于操作的优势，因此是分析纳米粒子悬浮液尺寸和尺寸分布的首选仪器。然而，许多 DLS 用户不熟悉 DLS 测量背后的原理，也不知道该技术的一些内在限制和独特功能。对 DLS 的理解不足往往导致实验设计不当和数据解释错误。在本研究中，我们对一系列直径为 10 至 100nm 的柠檬酸稳定的 AuNPs 进行了 DLS 分析。我们的研究表明，AuNPs 的测量流体力学直径可以随浓度和入射激光功率显著变化。AuNPs 的散射光强度与直径呈近六次方的幂律增加，直径在 80nm 左右或超过 80nm 的 AuNPs 的巨大散射光强度在常规 DLS 仪器中会产生显著的多重散射效应。这种效应会导致在没有考虑多重散射的情况下，按常规方法分析时，报告的 AuNPs 平均流体力学直径出现显著误差。我们在这里提出了一些有用的方法，可使用 DLS 获得 AuNPs 的准确流体力学尺寸。我们还展示并解释了 DLS 的一个极其强大的方面——其在检测金纳米粒子聚集形成方面的极高灵敏度，并展示了如何将这一独特功能应用于化学和生物传感应用。
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