Nanomechanical assessment of human and murine collagen fibrils via atomic force microscopy cantilever-based nanoindentation
Nanomechanical assessment of human and murine collagen fibrils via atomic force microscopy cantilever-based nanoindentation
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DOI：
10.1016/j.jmbbm.2014.06.015
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发表时间：
2014-11-01
影响因子：
3.9
通讯作者：
Thurner, Philipp J.
中科院分区：
文献类型：
--
作者：
Andriotis, Orestis G.;Manuyakorn, Wiparat;Thurner, Philipp J.
通过原子力显微镜 (AFM) 对胶原原纤维进行纳米力学评估在生物医学研究界引起了越来越多的兴趣。与传统的纳米压痕相比，不存在进行实验和数据分析的通用标准。目前使用的分析方法因研究而异，并且通常不进行定量结果的验证，这使得比较不同研究的数据变得困难。此外，对于为避免基材效应而不得超过的最大压痕深度，也没有任何建议。在这里，我们提出了一种基于 AFM 悬臂的纳米压痕实验的方法和分析方法，可以有效地利用捕获的数据并依靠参考样本来确定尖端形状。此外，我们还展示了实验证据，表明胶原纤维上的最大压痕深度应低于原纤维高度的 10-15%，以避免基质效应，并且我们展示了我们的方法与之前工作中使用的其他方法之间的比较。虽然我们的分析方法产生的压痕模量值与 Oliver-Pharr 方法相似，但我们发现赫兹分析产生的值明显较低。应用我们的方法，我们成功有效地从人类支气管中压印出胶原纤维，其尺寸约为 30 nm，与从鼠尾腱获得的胶原纤维相比要小得多。此外，得出的胶原原纤维的机械参数与先前发表的数据一致。为了建立定量验证，我们比较了传统纳米压痕和基于 AFM 悬臂梁的纳米压痕在具有已知机械性能的聚合物样品上的压痕结果。重要的是，我们可以证明，与聚合物样品上的传统纳米压痕相比，我们的方法产生了相似的结果。引入一种可靠、高效并考虑到 AFM 尖端形状的方法，我们预计目前的工作可以作为进行基于 AFM 悬臂的胶原纤维纳米压痕的指南。这可能有助于了解与胶原蛋白相关的疾病，例如哮喘、肺纤维化或骨病，以及胶原纤维力学的潜在改变。皇冠版权所有 (C) 2014 由 Elsevier Ltd 出版。保留所有权利。
The nanomechanical assessment of collagen fibrils via atomic force microscopy (AFM) is of increasing interest within the biomedical research community. In contrast to conventional nanoindentation there exists no common standard for conducting experiments and analysis of data. Currently used analysis approaches vary between studies and validation of quantitative results is usually not performed, which makes comparison of data from different studies difficult. Also there are no recommendations with regards to the maximum indentation depth that should not be exceeded to avoid substrate effects. Here we present a methodology and analysis approach for AFM cantilever-based nanoindentation experiments that allows efficient use of captured data and relying on a reference sample for determination of tip shape. Further we show experimental evidence that maximum indentation depth on collagen fibrils should be lower than 10-15% of the height of the fibril to avoid substrate effects and we show comparisons between our and other approaches used in previous works. While our analysis approach yields similar values for indentation modulus compared to the Oliver-Pharr method we found that Hertzian analysis yielded significantly lower values. Applying our approach we successfully and efficiently indented collagen fibrils from human bronchi, which were about 30 nm in size, considerably smaller compared to collagen fibrils obtained from murine tail-tendon. In addition, derived mechanical parameters of collagen fibrils are in agreement with data previously published. To establish a quantitative validation we compared indentation results from conventional and AFM cantilever-based nanoindentation on polymeric samples with known mechanical properties. Importantly we can show that our approach yields similar results when compared to conventional nanoindentation on polymer samples. Introducing an approach that is reliable, efficient and taking into account the AFM tip shape, we anticipate that the present work may act as a guideline for conducting AFM cantilever-based nanoindentation of collagen fibrils. This may aid understanding of collagen-related diseases such as asthma, lung fibrosis or bone disease with potential alterations of collagen fibril mechanics. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.