Abstract

Soft and biological materials are often composed of elementary constituents exhibiting an incessant roto-translational motion at the microscopic scale. Tracking this motion with a bright-field microscope becomes increasingly challenging when the particle size becomes smaller than the microscope resolution, a case which is frequently encountered. Here we demonstrate squared-gradient differential dynamic microscopy (SG-DDM) as a tool to successfully use bright-field microscopy to extract the roto-translational dynamics of small anisotropic colloidal particles, whose rotational motion cannot be tracked accurately in direct space. We provide analytical justification and experimental demonstration of the method by successful application to an aqueous suspension of peanut-shaped particles.

Graphic abstract

中文翻译：

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用明场显微镜探测各向异性小胶体颗粒的旋转平移扩散

摘要

柔软的生物材料通常由基本成分组成，这些基本成分在微观尺度上表现出不断的旋转平移运动。当粒径变得小于显微镜分辨率时，使用明场显微镜跟踪该运动变得越来越具有挑战性，这种情况经常遇到。在这里，我们展示了平方梯度微分动态显微镜（SG-DDM）作为成功使用明场显微镜提取各向异性小胶体颗粒旋转运动的工具，该小胶体颗粒的旋转运动无法在直接空间中精确跟踪。通过成功应用于花生形颗粒的水悬浮液，我们提供了该方法的分析论证和实验证明。

图形摘要