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

资源减少的人类人口持续增长，对负担得起和可持续的食物和营养提出了重大挑战。一种资源高效的解决方案是培养肉，这是通过直接使用生物反应器培养动物细胞生产的真正的动物肉。尽管基于脚手架的技术已经证明了制造碎肉或非结构化肉类产品的可行性，但这种技术是有限的，无法生产厚重的结构性肉类。这一早期概念探索性研究补助金(AGERGE)支持旨在建立无支架3D嵌入式生物打印技术的基础研究，从而能够生产出具有厘米厚和结构特征的养殖肉类。这项研究将探索成肌细胞在明胶复合材料细胞基质浴中嵌入肉类印花过程中的排列和融合。这一结果将促进未来规模化养殖肉类的规模化生产，并促进细胞农业作为补充食品生产的未来，以促进可持续发展、公共卫生和动物福利。该项目还将促进基于科学的生物印刷研究，以促进培养肉类的制造，并通过生物印刷研究扩大代表不足的学生在横切STEM领域的参与。本研究的目的是了解挤压诱导的剪切力和印刷后张力对成肌细胞在厚重的多细胞结构肉类组织嵌入印刷过程中形成排列的肌肉纤维的影响。具体地说，成肌细胞将以嵌入的方式打印、排列和拉伸，以便成肌细胞融合成肌管，并在明胶复合材料的屈服应力基质浴中进一步成熟为肌纤维。然后，印刷的牺牲生物墨水将被移除，以形成可灌装的通道。虽然成肌细胞和脂肪细胞前体细胞的嵌入式3D打印将使打印组织结构化，但由内皮干细胞和脂肪来源的干细胞自组装的可灌流的通道和毛细血管将使打印组织变厚。从理论上讲，印刷过程中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，成肌细胞将被宏观地视为成肌细胞生物墨水中的线弹性固体。建模结果将与打印的成肌细胞的取向进行验证。接下来，在定制的生物反应器中培养打印的肉样组织时，将研究循环张力对成肌细胞融合的影响，打印的组织将通过通道进行灌流。由此产生的肉样组织将在血管形成、成肌细胞分化以及肌管和肌纤维形成方面具有特征。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.