Colloid surface chemistry critically affects multiple particle tracking measurements of biomaterials.
Colloid surface chemistry critically affects multiple particle tracking measurements of biomaterials.
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DOI：
10.1529/biophysj.103.037812
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发表时间：
2004-06
影响因子：
3.4
通讯作者：
M. Valentine;Z. Perlman;M. Gardel;J. Shin;P. Matsudaira;T. Mitchison;D. Weitz
中科院分区：
文献类型：
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作者：
M. Valentine;Z. Perlman;M. Gardel;J. Shin;P. Matsudaira;T. Mitchison;D. Weitz
使用微流变技术表征复杂的生物材料的特性有希望提供基本的见解，他们的生物力学功能，然而，这种测量的精确解释是阻碍了不充分的表征示踪剂和网络之间的相互作用，他们探测。我们在这里表明，胶体表面化学可以深刻地影响多个粒子跟踪测量网络的纤维蛋白，纠缠的F-肌动蛋白的解决方案，和网络的交联的F-肌动蛋白。我们提出了一个简单的协议，使胶体探针颗粒的表面蛋白质抗性的接枝短胺封端的甲氧基聚（乙二醇）的羧基化微球的表面。我们证明，这些聚（乙二醇）包被的示踪剂吸附显着减少蛋白质比颗粒包被牛血清白蛋白或未改性的探针颗粒。我们建立了不同的颗粒表面化学选择性地调整颗粒的敏感性，以不同的物理性质，他们的微环境。具体而言，弱结合到异质网络的颗粒对网络刚度的变化敏感，而抗蛋白质示踪剂测量流体粘度和网络微观结构的变化。我们的实验表明，两个粒子的微观流变学分析显着减少示踪剂表面化学所产生的差异，表明修改网络特性附近的粒子不引入大规模的异质性。我们的研究结果表明，控制胶体-蛋白质相互作用是成功应用多粒子跟踪技术重建蛋白质网络，细胞质和细胞的关键。
Characterization of the properties of complex biomaterials using microrheological techniques has the promise of providing fundamental insights into their biomechanical functions; however, precise interpretations of such measurements are hindered by inadequate characterization of the interactions between tracers and the networks they probe. We here show that colloid surface chemistry can profoundly affect multiple particle tracking measurements of networks of fibrin, entangled F-actin solutions, and networks of cross-linked F-actin. We present a simple protocol to render the surface of colloidal probe particles protein-resistant by grafting short amine-terminated methoxy-poly(ethylene glycol) to the surface of carboxylated microspheres. We demonstrate that these poly(ethylene glycol)-coated tracers adsorb significantly less protein than particles coated with bovine serum albumin or unmodified probe particles. We establish that varying particle surface chemistry selectively tunes the sensitivity of the particles to different physical properties of their microenvironments. Specifically, particles that are weakly bound to a heterogeneous network are sensitive to changes in network stiffness, whereas protein-resistant tracers measure changes in the viscosity of the fluid and in the network microstructure. We demonstrate experimentally that two-particle microrheology analysis significantly reduces differences arising from tracer surface chemistry, indicating that modifications of network properties near the particle do not introduce large-scale heterogeneities. Our results establish that controlling colloid-protein interactions is crucial to the successful application of multiple particle tracking techniques to reconstituted protein networks, cytoplasm, and cells.