Optically based-indentation technique for acute rat brain tissue slices and thin biomaterials
Optically based-indentation technique for acute rat brain tissue slices and thin biomaterials
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DOI：
10.1002/jbm.b.31789
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发表时间：
2011-04-01
影响因子：
3.4
通讯作者：
Sarntinoranont, M.
中科院分区：
文献类型：
--
作者：
Lee, S. J.;Sun, J.;Sarntinoranont, M.
目前，由于累积的仪器漂移误差，软生物材料的微压痕测试在长时间尺度上的测试能力受到限制。因此，缺乏诸如平衡模量之类的机械性能的测量。在这项研究中，压痕结合光学相干断层扫描（OCT）用于薄组织切片的力学测试。将球形微珠置于浸没的测试样本上后，使用OCT测量表面变形曲线。使用该技术在30分钟的时间窗内测试低浓度（w/v，0.3-0.6%）的基于琼脂糖的水凝胶和急性大鼠脑组织切片。为了确定组织切片保持细胞活力，通过用Fluor-Jade C（FJC）染色测量作为孵育时间函数的神经元死亡或变性来确定允许的测试时间。由于在平衡时测量到大的变形，因此将表面珠的位移与有限元弹性接触模拟进行比较，以预测平衡模量μ（无穷大）μ值对于低浓度水凝胶，压力（无穷大）的范围为0.07至1.8kPa，而μ（无穷大）急性大鼠脑组织切片的皮质为0.13 +/-0.04kPa，海马为0.09 +/-0.015kPa（泊松比= 0.35）。这种压痕技术为非常软的材料的长时间尺度机械测试提供了一种本地化、实时和高分辨率的方法。该试验方法也适用于粘弹性，用于不同组织和生物材料的试验，以及用于分析内部结构随载荷的变化。(C)2011 Wiley Periodicals，Inc. J Biomed Mater Res Part B：Appl Biomater 97 B：84-95，2011.
Currently, micro-indentation testing of soft biological materials is limited in its capability to test over long time scales due to accumulated instrumental drift errors. As a result, there is a paucity of measures for mechanical properties such as the equilibrium modulus. In this study, indentation combined with optical coherence tomography (OCT) was used for mechanical testing of thin tissue slices. OCT was used to measure the surface deformation profiles after placing spherical beads onto submerged test samples. Agarose-based hydrogels at low-concentrations (w/v, 0.3-0.6%) and acute rat brain tissue slices were tested using this technique over a 30-min time window. To establish that tissue slices maintained cell viability, allowable testing times were determined by measuring neuronal death or degeneration as a function of incubation time with Fluor-Jade C (FJC) staining. Since large deformations at equilibrium were measured, displacements of surface beads were compared with finite element elastic contact simulations to predict the equilibrium modulus, mu(infinity) Values of mu(infinity) for the low-concentration hydrogels ranged from 0.07 to 1.8 kPa, and mu(infinity) acute rat brain tissue slices was 0.13 +/- 0.04 kPa for the cortex and 0.09 +/- 0.015 kPa for the hippocampus (for Poisson ratio = 0.35). This indentation technique offers a localized, real-time, and high resolution method for long-time scale mechanical testing of very soft materials. This test method may also be adapted for viscoelasticity, for testing of different tissues and biomaterials, and for analyzing changes in internal structures with loading. (C) 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 97B: 84-95, 2011.