Anisotropic freeze-cast collagen scaffolds for tissue regeneration: How processing conditions affect structure and properties in the dry and fully hydrated states.
Anisotropic freeze-cast collagen scaffolds for tissue regeneration: How processing conditions affect structure and properties in the dry and fully hydrated states.
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DOI：
10.1016/j.jmbbm.2018.09.012
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发表时间：
2019-03
影响因子：
3.9
通讯作者：
Wegst UGK
中科院分区：
文献类型：
--
作者：
Divakar P;Yin K;Wegst UGK
关于定向冷冻铸造生物聚合物支架的系统结构-性能-加工相关性的报道很少。这种相关性对于支架设计在体内具有有吸引力的结构和机械线索至关重要。本研究重点关注具有三种不同应用冷却速率（10、1 和 0.1°C/min）和两种冷冻方向（纵向和径向）的冷冻铸造胶原支架。开发了一种通过共焦显微镜对完全水合支架进行结构表征的半自动化方法，以促进结构特征的客观量化和比较。此外，还进行了纵向和横向的扫描电子显微镜和压缩测试。结构和机械性能是在干燥和完全水合的支架上确定的。纵向冷冻支架具有排列整齐的规则孔，而径向冷冻支架的孔几何形状和排列表现出更大的变化。层间距、孔面积和细胞壁厚度随着冷却速率的降低而增加：在纵向冷冻支架中，从 25 μm 到 83.5 μm、814 μm2 到 8,452 μm2、4.21 μm 到 10.4 μm；在径向冷冻支架中，从 69 μm 到 116 μm、7,679 μm2 到分别为 25,670 μm2 和 6.18 μm 至 13.6 μm。当平行于而不是垂直于冰晶生长方向加载时，纵向和径向冷冻支架都具有更高的机械性能值。模量和屈服强度范围分别为 779–4,700 kPa 和 38–137 kPa，是冷却速率和冷冻方向的函数。经过整理，本研究中获得的相关性使得冻铸胶原支架的定制设计成为可能，该支架非常适合各种组织再生应用。
Few systematic structure–property-processing correlations for directionally freeze-cast biopolymer scaffolds are reported. Such correlations are critical to enable scaffold design with attractive structural and mechanical cues in vivo. This study focuses on freeze-cast collagen scaffolds with three different applied cooling rates (10, 1, and 0.1°C/min) and two freezing directions (longitudinal and radial). A semi-automated approach for structural characterization of fully hydrated scaffolds by confocal microscopy is developed to facilitate an objective quantification and comparison of structural features. Additionally, scanning electron microscopy, and compression testing are performed longitudinally and transversely. Structural and mechanical properties are determined on dry and fully hydrated scaffolds. Longitudinally-frozen scaffold have aligned and regular pores while those in radially-frozen ones exhibit greater variations in pore geometry and alignment. Lamellar spacing, pore area, and cell wall thickness increase with decreasing cooling rate: in longitudinally-frozen scaffolds from 25 μm to 83.5 μm, 814 μm2 to 8,452 μm2, and 4.21 μm to 10.4 μm, and in radially-frozen ones, from 69 μm to 116 μm, 7,679 μm2 to 25,670 μm2, and 6.18 μm to 13.6 μm, respectively. Both longitudinally- and radially-frozen scaffolds possess higher mechanical property values, when loaded parallel rather than perpendicular to the ice-crystal growth direction. Modulus and yield strength range from 779–4,700 kPa and 38–137 kPa, respectively, as a function of cooling rate and freezing direction. Collated, the correlations obtained in this study enable the custom-design of freeze-cast collagen scaffolds, which are ideally suited for a large variety of tissue regeneration applications.
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影响因子：
4.9
作者：
Francis, Nicola L.;Hunger, Philipp M.;Wheatley, Margaret A.
通讯作者：
Wheatley, Margaret A.
影响因子：
14
作者：
Bozkurt, Ahmet;Lassner, Franz;Pallua, Norbert
通讯作者：
Pallua, Norbert
DOI：
10.1007/s10856-016-5763-9
发表时间：
2016-10
期刊：
Journal of materials science. Materials in medicine
影响因子：
--
作者：
Davidenko N;Schuster CF;Bax DV;Farndale RW;Hamaia S;Best SM;Cameron RE
通讯作者：
Cameron RE
影响因子：
--
作者：
Bozkurt, Ahmet;Brook, Gary A.;Pallua, Norbert
通讯作者：
Pallua, Norbert
影响因子：
9.7
作者：
Davidenko, N.;Gibb, T.;Cameron, R. E.
通讯作者：
Cameron, R. E.