Offeddu Giovanni S, Ashworth Jennifer C, Cameron Ruth E, Oyen Michelle L
Engineering Department, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK; Cambridge Centre for Medical Materials, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK.
Cambridge Centre for Medical Materials, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK.
J Mech Behav Biomed Mater. 2015 Feb;42:19-25. doi: 10.1016/j.jmbbm.2014.10.015. Epub 2014 Nov 11.
Tissue engineering has grown in the past two decades as a promising solution to unresolved clinical problems such as osteoarthritis. The mechanical response of tissue engineering scaffolds is one of the factors determining their use in applications such as cartilage and bone repair. The relationship between the structural and intrinsic mechanical properties of the scaffolds was the object of this study, with the ultimate aim of understanding the stiffness of the substrate that adhered cells experience, and its link to the bulk mechanical properties. Freeze-dried type I collagen porous scaffolds made with varying slurry concentrations and pore sizes were tested in a viscoelastic framework by macroindentation. Membranes made up of stacks of pore walls were indented using colloidal probe atomic force microscopy. It was found that the bulk scaffold mechanical response varied with collagen concentration in the slurry consistent with previous studies on these materials. Hydration of the scaffolds resulted in a more compliant response, yet lesser viscoelastic relaxation. Indentation of the membranes suggested that the material making up the pore walls remains unchanged between conditions, so that the stiffness of the scaffolds at the scale of seeded cells is unchanged; rather, it is suggested that thicker pore walls or more of these result in the increased moduli for the greater slurry concentration conditions.
在过去二十年中，组织工程学蓬勃发展，成为解决诸如骨关节炎等尚未解决的临床问题的一种有前景的方法。组织工程支架的力学响应是决定其在软骨和骨修复等应用中使用的因素之一。支架的结构和固有力学性能之间的关系是本研究的对象，其最终目的是了解黏附细胞所经历的基质的刚度及其与整体力学性能的联系。通过宏观压痕在粘弹性框架中测试了用不同浆料浓度和孔径制成的冻干I型胶原多孔支架。使用胶体探针原子力显微镜对由孔壁堆叠组成的膜进行压痕。结果发现，与之前对这些材料的研究一致，整体支架的力学响应随浆料中胶原蛋白浓度的变化而变化。支架的水合作用导致更柔顺的响应，但粘弹性松弛较小。对膜的压痕表明，构成孔壁的材料在不同条件下保持不变，因此在接种细胞尺度上支架的刚度不变；相反，有人认为，更厚的孔壁或更多的孔壁会导致在更高浆料浓度条件下模量增加。
