Measuring colloid–surface interaction forces in parallel using fluorescence centrifuge force microscopy
Measuring colloid–surface interaction forces in parallel using fluorescence centrifuge force microscopy
复制标题
使用荧光离心力显微镜并行测量胶体与表面相互作用力
DOI：
10.1039/d1sm00461a
复制
发表时间：
2021
期刊：
影响因子：
3.4
通讯作者：
Wilking, James N.
中科院分区：
文献类型：
--
作者：
LeFevre, Thomas B.;Bikos, Dimitri A.;Chang, Connie B.;Wilking, James N.
胶体尺度结构之间的相互作用决定了软材料和生物材料的物理特性，而与这些相互作用相关的力的知识对于理解和控制这些材料至关重要。量化胶体相互作用的常用方法是测量胶体与固定表面之间的相互作用力。离心力显微镜（CFM）是一种位于离心机内部的微型显微镜，能够在很宽的力范围（10−2至104 pN）内并行执行数百个力测量，但CFM仪器并不广泛用于测量胶体表面相互作用力。此外，目前的CFM仪器依赖于明场照明，不能进行荧光显微镜检查。在这里，我们提出了一种荧光CFM（F-CFM），结合了荧光和明场显微镜，并证明其用于测量微尺度胶体表面相互作用力。F-CFM的运行速度高达5000 RPM，比之前报道的速度快2.5倍，产生的最大力比之前的仪器大6.25倍。电池供电的GoPro摄像机可在移动终端上实时查看显微镜视频，音频信号的频率分析将离心机转速与视频信号相关联。为了证明的能力的F-CFM，我们测量所需的力，以分离数百个静电稳定的胶体微球附着到带电的玻璃表面的离子强度的函数，并比较所得的力分布与近似的DLVO理论。F-CFM将使微尺度力测量与软和生物系统中的荧光成像相关联。
Interactions between colloidal-scale structures govern the physical properties of soft and biological materials, and knowledge of the forces associated with these interactions is critical for understanding and controlling these materials. A common approach to quantify colloidal interactions is to measure the interaction forces between colloids and a fixed surface. The centrifuge force microscope (CFM), a miniaturized microscope inside a centrifuge, is capable of performing hundreds of force measurements in parallel over a wide force range (10−2 to 104 pN), but CFM instruments are not widely used to measure colloid–surface interaction forces. In addition, current CFM instruments rely on brightfield illumination and are not capable of fluorescence microscopy. Here we present a fluorescence CFM (F-CFM) that combines both fluorescence and brightfield microscopy and demonstrate its use for measuring microscale colloidal-surface interaction forces. The F-CFM operates at speeds up to 5000 RPM, 2.5× faster than those previously reported, yielding a 6.25× greater maximum force than previous instruments. A battery-powered GoPro video camera enables real-time viewing of the microscopy video on a mobile device, and frequency analysis of the audio signal correlates centrifuge rotational speed with the video signal. To demonstrate the capability of the F-CFM, we measure the force required to detach hundreds of electrostatically stabilized colloidal microspheres attached to a charged glass surface as a function of ionic strength and compare the resulting force distributions with an approximated DLVO theory. The F-CFM will enable microscale force measurements to be correlated with fluorescence imaging in soft and biological systems.