Kontomaris Stylianos Vasileios, Stylianou Andreas, Malamou Anna
Faculty of Engineering and Architecture, Metropolitan College, 15125 Athens, Greece.
BioNanoTec LTD, 2043 Nicosia, Cyprus.
Materials (Basel). 2022 Mar 27;15(7):2477. doi: 10.3390/ma15072477.
Atomic Force Microscopy nanoindentation method is a powerful technique that can be used for the nano-mechanical characterization of bio-samples. Significant scientific efforts have been performed during the last two decades to accurately determine the Young's modulus of collagen fibrils at the nanoscale, as it has been proven that mechanical alterations of collagen are related to various pathological conditions. Different contact mechanics models have been proposed for processing the force-indentation data based on assumptions regarding the shape of the indenter and collagen fibrils and on the elastic or elastic-plastic contact assumption. However, the results reported in the literature do not always agree; for example, the Young's modulus values for dry collagen fibrils expand from 0.9 to 11.5 GPa. The most significant parameters for the broad range of values are related to the heterogeneous structure of the fibrils, the water content within the fibrils, the data processing errors, and the uncertainties in the calibration of the probe. An extensive discussion regarding the models arising from contact mechanics and the results provided in the literature is presented, while new approaches with respect to future research are proposed.
原子力显微镜纳米压痕法是一种强大的技术，可用于生物样品的纳米力学表征。在过去二十年中，人们进行了大量科学研究，以准确测定纳米尺度下胶原纤维的杨氏模量，因为已证明胶原的力学改变与各种病理状况有关。基于关于压头和胶原纤维形状的假设以及弹性或弹塑性接触假设，已经提出了不同的接触力学模型来处理力-压痕数据。然而，文献中报道的结果并不总是一致；例如，干胶原纤维的杨氏模量值从0.9 GPa到11.5 GPa不等。造成如此宽泛取值范围的最重要参数与纤维的异质结构、纤维内的含水量、数据处理误差以及探头校准的不确定性有关。本文对接触力学产生的模型以及文献中提供的结果进行了广泛讨论，同时提出了关于未来研究的新方法。
