A scratch test using a nanoindentation system was proposed in this study to assess the age-related changes in the in situ toughness of bone matrix at ultrastructural levels. A tissue removal energy density (ur) was defined and estimated as the work done by the scratch (UT) divided by the total volume of the scratch groove (us). The value of us was used as a relative measure of the in situ toughness of the tissue. Human cortical bone specimens obtained from middle-aged (between 49 and 59 years old) and elderly groups (over 69 years old) were tested using this technique. A significant difference in the estimated removal energy density (us) in the secondary osteons was found between the middle-aged and elderly groups (5.49±0.696 vs. 4.09±1.30 N/mm2, respectively).
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机译：在这项研究中提出了使用纳米压痕系统的划痕测试，以评估在超微结构水平下与年龄相关的骨基质原位韧性变化。定义组织去除能量密度（ur）并将其估算为通过刮擦（UT）完成的功除以刮擦凹槽的总体积（us）。 us的值用作组织原位韧性的相对度量。使用该技术测试了从中年（49至59岁之间）和老年人（69岁以上）中获得的人类皮质骨标本。在中老年人组中，次生骨的估计去除能量密度（us）存在显着差异（分别为5.49±0.696和4.09±1.30 N / mm 2 ）。
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