评估生物墨水的形状保真度,以辅助 3D 生物打印中的材料开发。
Assessing bioink shape fidelity to aid material development in 3D bioprinting.
机构信息
Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.
出版信息
Biofabrication. 2017 Nov 30;10(1):014102. doi: 10.1088/1758-5090/aa90e2.
During extrusion-based bioprinting, the deposited bioink filaments are subjected to deformations, such as collapse of overhanging filaments, which compromises the ability to stack several layers of bioink, and fusion between adjacent filaments, which compromises the resolution and maintenance of a desired pore structure. When developing new bioinks, approaches to assess their shape fidelity after printing would be beneficial to evaluate the degree of deformation of the deposited filament and to estimate how similar the final printed construct would be to the design. However, shape fidelity has been prevalently assessed qualitatively through visual inspection after printing, hampering the direct comparison of the printability of different bioinks. In this technical note, we propose a quantitative evaluation for shape fidelity of bioinks based on testing the filament collapse on overhanging structures and the filament fusion of parallel printed strands. Both tests were applied on a hydrogel platform based on poloxamer 407 and poly(ethylene glycol) blends, providing a library of hydrogels with different yield stresses. The presented approach is an easy way to assess bioink shape fidelity, applicable to any filament-based bioprinting system and able to quantitatively evaluate this aspect of printability, based on the degree of deformation of the printed filament. In addition, we built a simple theoretical model that relates filament collapse with bioink yield stress. The results of both shape fidelity tests underline the role of yield stress as one of the parameters influencing the printability of a bioink. The presented quantitative evaluation will allow for reproducible comparisons between different bioink platforms.
在基于挤出的生物打印过程中,沉积的生物墨水细丝会发生变形,例如悬空细丝的坍塌,这会影响堆叠多层生物墨水的能力,以及相邻细丝之间的融合,这会影响所需孔结构的分辨率和保持。在开发新的生物墨水时,评估其打印后的形状保真度的方法将有助于评估沉积细丝的变形程度,并估计最终打印的结构与设计的相似程度。然而,形状保真度通常是通过打印后的视觉检查进行定性评估的,这阻碍了不同生物墨水可印刷性的直接比较。在本技术说明中,我们提出了一种基于测试悬垂结构上细丝坍塌和平行打印丝之间细丝融合的生物墨水形状保真度的定量评估方法。这两个测试都应用于基于泊洛沙姆 407 和聚乙二醇共混物的水凝胶平台,提供了具有不同屈服应力的水凝胶库。所提出的方法是评估生物墨水形状保真度的一种简单方法,适用于任何基于细丝的生物打印系统,并能够根据打印细丝的变形程度,定量评估可印刷性的这一方面。此外,我们建立了一个简单的理论模型,将细丝坍塌与生物墨水屈服应力联系起来。这两种形状保真度测试的结果强调了屈服应力作为影响生物墨水可印刷性的参数之一的作用。所提出的定量评估将允许在不同的生物墨水平台之间进行可重复的比较。