Ekpenyong Andrew E, Posey Carolyn L, Chaput Joy L, Burkart Anya K, Marquardt Meg M, Smith Timothy J, Nichols Michael G
Department of Physics, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, USA.
Appl Opt. 2009 Nov 10;48(32):6344-54. doi: 10.1364/AO.48.006344.
The optical stretcher is a dual-beam trap capable of stretching individual cells. Previous studies have used either ray- or wave-optical models to compute the optical pressure on the surface of a spherical cell. We have extended the ray-optics model to account for focusing by the spherical interface and the effects of multiple internal reflections. Simulation results for red-blood cells (RBCs) show that internal reflections can lead to significant perturbation of the deformation, leading to a systematic error in the determination of cellular elasticity. Calibration studies show excellent agreement between the predicted and measured escape force, and RBC stiffness measurements are consistent with literature values. Measurements of the elasticity of murine osteogenic cells reveal that these cells are approximately 5.4 times stiffer than RBCs.
光镊是一种能够拉伸单个细胞的双光束阱。先前的研究使用射线光学或波动光学模型来计算球形细胞表面的光压力。我们扩展了射线光学模型，以考虑球形界面的聚焦和多次内部反射的影响。红细胞（RBC）的模拟结果表明，内部反射会导致变形的显著扰动，从而在细胞弹性测定中产生系统误差。校准研究表明，预测的逃逸力与测量值之间具有极好的一致性，并且红细胞硬度测量结果与文献值一致。对小鼠成骨细胞弹性的测量表明，这些细胞的硬度约为红细胞的5.4倍。
