EAGER: 3D Printing of Aligned Muscle Fibers for Thick Structured Meat Production

人口持续增长，资源减少，对负担得起和可持续的粮食和营养构成了重大挑战。一种资源节约型的解决方案是培养肉，这是通过使用生物反应器直接培养动物细胞生产的真正的动物肉。虽然基于支架的技术已经证明了制造切碎或非结构化肉类产品的可行性，但这些技术是有限的，不能生产厚的结构化肉类。EARLY概念探索性研究资助（EAGER）支持基础研究，旨在建立无支架3D嵌入式生物打印技术，以生产具有厘米厚和结构特征的培养肉。该研究将探讨在明胶复合物为基础的细胞基质浴中嵌入式肉类打印过程中成肌细胞的排列和融合。研究结果将促进未来培养肉厚结构切片的规模化生产，并促进细胞农业作为未来补充食品生产的可持续性，公共卫生和动物福利。该项目还将刺激基于科学的生物打印研究，以推进培养肉制造，并通过生物打印研究扩大代表性不足的学生在交叉STEM领域的参与。本研究的目的是了解在嵌入式打印厚多细胞结构的肉样组织期间，挤压诱导的剪切力和打印后张力对成肌细胞形成对齐肌纤维的影响。具体地，成肌细胞将以包埋方式打印、对齐和拉伸，以使成肌细胞融合为肌管，并在基于明胶复合物的屈服应力基质浴中进一步成熟为肌纤维。然后将去除打印的牺牲生物墨水以形成可灌注通道。虽然成肌细胞和脂肪细胞祖细胞的嵌入式3D打印将使打印的组织结构化，但由内皮和脂肪源性干细胞自组装的可灌注通道和毛细血管将使打印的组织变厚。理论上，在打印期间剪切力对成肌细胞排列的影响将使用欧拉公式进行计算建模，并且成肌细胞将在成肌细胞生物墨水中被宏观地视为线性弹性固体。将使用打印的成肌细胞的方向来验证建模结果。接下来，在定制的生物反应器中培养打印的肉样组织期间，将研究循环张力诱导对成肌细胞融合的影响，并且打印的组织将通过通道灌注。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

The continued growth of human populations with declined resources has imposed a significant challenge to affordable and sustainable foods and nutrition. One resource-efficient solution is cultured meat, which is genuine animal meat produced by cultivating animal cells directly using a bioreactor. Though scaffold-based technologies have demonstrated the feasibility of making minced or unstructured meat products, such technologies are limited and cannot produce thick structured meat. This EArly-concept Grant for Exploratory Research (EAGER) supports fundamental research that aims to establish a scaffold-free 3D embedded bioprinting technology to enable the production of cultured meat with centimeter thick and structured features. The study will explore the alignment and fusion of myoblasts during embedded meat printing in a gelatin composite-based cellular matrix bath. The results will catalyze future scale-up production of thick structured cuts of cultured meat and promote cellular agriculture as the future of complementary food production for the benefits of sustainability, public health, and animal welfare. The project will also stimulate science-based bioprinting research to advance cultured-meat manufacture and broaden the participation of underrepresented students in crosscutting STEM fields via the bioprinting study.The objective of this research is to understand the effects of extrusion-induced shear force and post-printing tension on the formation of aligned muscle fibers from myoblasts during embedded printing of thick multicellular structured meat-like tissues. Specifically, myoblasts will be printed in an embedded manner, aligned, and stretched for myoblast fusion to be myotubes and further matured as myofibers in the gelatin composite-based yield-stress matrix bath. The printed sacrificial bioink will then be removed to form perfusable channels. While embedded 3D printing of myoblasts and adipocyte progenitor cells will enable printed tissues to be structured, the perfusable channels and capillaries self-assembled by endothelial and adipose-derived stem cells will enable the printed tissues to grow thick. Theoretically, the effect of shear force on the myoblast alignment during printing will be computationally modeled using the Eulerian formulation and myoblasts will be macroscopically treated as a linear elastic solid in the myoblast bioink. The modeling results will be validated with the orientation of the printed myoblasts. Next, the cyclic tension-induced effect on myoblast fusion will be investigated during the culturing of the printed meat-like tissues in a customized bioreactor, and the printed tissues will be perfused via the channels. The resulting meat-like tissues will be characterized in terms of vascularization, myoblast differentiation as well as myotube and myofiber formation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.