Computational study of extrusion bioprinting with jammed gelatin microgel-based composite ink
Computational study of extrusion bioprinting with jammed gelatin microgel-based composite ink
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DOI：
10.1016/j.addma.2021.101963
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发表时间：
2021-05-01
影响因子：
11
通讯作者：
Huang, Yong
中科院分区：
文献类型：
--
作者：
Song, Kaidong;Zhang, Deming;Huang, Yong
材料挤出是一种基于生物材料的三维生物打印技术，因其效率高、与多种生物材料相容性好、易于实现等优点，被广泛应用于制造复杂结构。在挤出生物打印过程中，挤出长丝的形态（包括形状和尺寸）非常重要，因为长丝是打印3D结构的基本构建块，长丝形态决定了打印分辨率，表面质量和零件机械强度。本研究的目的是计算分析堵塞明胶微凝胶基复合油墨在挤出过程中的打印性能的长丝横截面形态和油墨屈服应力流体性质对结构印刷适性的影响。从流变学测量中可以看出，堵塞的明胶微凝胶复合油墨是具有剪切稀化性质的粘塑性流体，并且其屈服应力流体性质使其能够用于自支撑印刷应用。油墨印刷过程中已计算建模，通过使用一个合适的赫歇尔？Bulkley模型首次模拟了明胶微凝胶复合油墨的堵塞行为，取得了良好的建模效果。特别是，在不同的打印条件下的长丝横截面形态已令人满意地建模。研究发现，在较小的归一化间隙距离（小于0.6）下，横截面形状变成平坦的矩形。此外，已经令人满意地估计了沉积在两个支撑基底之间和支撑基底上的堵塞的明胶微凝胶基复合油墨的可实现的最大长度（没有塌陷）。
Material extrusion, a filament-based three-dimensional (3D) bioprinting technique, is commonly adopted to fabricate many complex constructs for its high efficiency, compatibility with a variety of biomaterials, and easy realization. During extrusion bioprinting, the morphology (including the shape and size) of extruded filaments is of great interest since the filaments are the basic building blocks for printed 3D structures and the filament morphology determines the printing resolution, surface quality, and part mechanical strength. The objective of this study is to computationally analyze the printing performance of the jammed gelatin microgel-based composite ink during extrusion in terms of the filament cross-sectional morphology and the influence of ink yieldstress fluid property on the structural printability. As seen from the rheological measurements, the jammed gelatin microgel composite ink is a viscoplastic fluid with the shear-thinning property, and its yield-stress fluid property enables it for self-supported printing applications. The ink printing process has been computationally modeled by using a fitted Herschel?Bulkley model to simulate the behavior of the jammed gelatin microgel composite ink for the first time, resulting in good modeling performance. In particular, the filament crosssectional morphology under different printing conditions has been satisfactorily modeled. It is found that the cross-sectional shape turns flat rectangular under a small normalized gap distance (less than 0.6). Furthermore, the achievable maximum length (without collapse) of the jammed gelatin microgel-based composite ink, deposited both between two supporting substrates and over a supporting substrate, has been satisfactorily estimated.