Static and dynamic errors in particle tracking microrheology
Static and dynamic errors in particle tracking microrheology
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DOI：
10.1529/biophysj.104.04245
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发表时间：
2005-01-01
影响因子：
3.4
通讯作者：
Doyle, PS
中科院分区：
文献类型：
--
作者：
Savin, T;Doyle, PS
粒子跟踪技术通常用于评估细胞和生物流体的局部机械性质。利用提取的轨迹来计算表征探针粒子的动力学的均方位移。有限的空间分辨率和统计不确定性是改变均方位移估计精度的限制因素。我们精确地量化了定位误差在均方位移的确定中的影响，通过将这些误差的来源分成两个单独的贡献。在固定粒子的位置测量中出现“静态误差”。“动态误差”来自可视化所需的有限曝光时间期间的粒子运动。我们计算了这些误差在均方位移上的传播。我们研究了我们的误差分析对生物流变学中使用的理论模型流体的影响。使用模拟和使用视频显微镜进行的多粒子跟踪技术，对纯粘性流体验证了这些理论预测。我们表明，静态的贡献，可以自信地在动态研究中进行校正，通过使用静态实验在一个类似的噪声-信号比。这一基础工作使我们能够在均方位移中实现更高的分辨率，从而提高微观流变学研究的准确性。
Particle tracking techniques are often used to assess the local mechanical properties of cells and biological fluids. The extracted trajectories are exploited to compute the mean-squared displacement that characterizes the dynamics of the probe particles. Limited spatial resolution and statistical uncertainty are the limiting factors that alter the accuracy of the mean-squared displacement estimation. We precisely quantified the effect of localization errors in the determination of the mean-squared displacement by separating the sources of these errors into two separate contributions. A "static error'' arises in the position measurements of immobilized particles. A "dynamic error'' comes from the particle motion during the finite exposure time that is required for visualization. We calculated the propagation of these errors on the mean-squared displacement. We examined the impact of our error analysis on theoretical model fluids used in biorheology. These theoretical predictions were verified for purely viscous fluids using simulations and a multiple-particle tracking technique performed with video microscopy. We showed that the static contribution can be confidently corrected in dynamics studies by using static experiments performed at a similar noise-to-signal ratio. This groundwork allowed us to achieve higher resolution in the mean-squared displacement, and thus to increase the accuracy of microrheology studies.