Converging biomechanical and biophysical approaches toward ligament and tendon regeneration

我的研究项目的总体目标是利用生物制造、生物工程和生物物理方法来驱动人类间充质干细胞分化为组织工程的韧带和肌腱。在美国报道的3300万例肌肉骨骼损伤中，肌腱和韧带损伤约占50%。这些组织的自我修复能力有限，目前自体移植物的金标准失败率很高，表明需要改进修复策略。肌腱组织工程旨在通过提供生物相容性材料作为体外或体内细胞重塑的支架来制造肌腱样组织，从而提供自体移植物的替代方案。然而，最适合肌腱样组织生长的细胞类型、支架设计和生物材料仍有待确定。间充质干细胞（Mesenchymal stem cells, MSCs）是一种多能和自我更新的细胞，在再生医学中显示出巨大的潜力。尽管用于韧带修复的MSCs的最佳类型仍有待确定。此外，韧带/肌腱组织需要机械刺激来促进细胞外基质基因的表达，但目前尚不清楚组织工程韧带结构是否能从机械激活中受益。为了成功地促进肌腱/韧带愈合的细胞分化和基质沉积，我们建议MSCs或MSCs种子支架应该经过机械激活和细胞排列，以获得最佳的细胞信号传导和基因表达。我们将应用新颖的3D打印技术来生成独特的几何支架，这些支架具有其他平台无法实现的生物物理和地形特性。我们的团队一直处于组织工程生物制造和体外人体组织建模应用的前沿。我们在使用独特的细胞培养平台进行人类原代细胞的机械/动态培养方面也有广泛的专业知识。这些方法将应用于以下目的：目标：1)评估纳米模式3D打印支架对干细胞播种和肌腱/韧带分化的影响。2)确定机械动态二维细胞培养对肌腱和韧带分化引发干细胞的影响。3)确定长期机械活性生物反应器培养对肌腱基质沉积和重塑的影响。多学科方法，包括生物材料科学，生物工程和细胞生物学专业知识，用于生成组织建模和组织工程的独特技术平台。这种生物制造技术的可用性将直接允许快速支架设计测试，并更好地理解生物物理和力学如何驱动韧带细胞分化。最后，这个研究项目可能为知识产权、商业化和与行业合作伙伴的互动开辟道路。

The overall goal of my research program is leverage biofabrication, bioengineering and biophysical approaches to drive human mesenchymal stem cell differentiation towards ligament and tendon for tissue engineering. Tendon and ligament injuries account for approximately 50% of the 33 million musculoskeletal injuries reported in the United States. These tissues have limited self-healing capacities, and the current gold-standard of autografts have high failure rates, showing the need for improved repair strategies. Tendon tissue engineering aims to provide alternative to autografts by providing a biocompatible material to act as a scaffold for cell remodelling in vitro or in vivo to fabricate a tendon-like tissue. However, the most suitable cell type, scaffold design and biomaterial remain to be determined for optimal tendon-like tissue growth. Mesenchymal stem cells (MSCs) are multipotent and self-renewing cells, which have shown great potential within regenerative medicine. Although the optimal type of MSCs for ligament repair remains to be identified. Furthermore, ligament/tendon tissues require mechanical stimulation for extracellular matrix gene expression, yet it remains unlcear whether tissue engineered ligament constructs could benefit from mechanical activation. To successfully promote cell differentiation and matrix deposition for tendon/ligament healing, we propose that MSCs or MSC-seeded scaffolds should undergo mechanoactivation and cellular alignemnt for optimal cell signaling and gene expression. We will apply novel 3D printing technologies to generate unique geometric scaffolds with biophysical and topographical properties not achievable in other platforms. Our group has been at the forefront of biofabrication for tissue engineering and in vitro human tissue modeling applications. We also have extensive expertise in mechanical/dynamic culture of primary human cells using unique cell cutlure platforms. These approaches will be applied in the following aims: Objectives: 1) Asses impact of nanopatterned 3D printed scaffolds on stem cell seeding, and tendon/ligament differentiation. 2) Determine the effects of mechanically dynamic 2D cell culture on priming stem cells for tendon and ligament differentiation. 3) Determine impact of long term mechanically active bioreactor culture on tendon matrix depostion and remodeling. Multidisciplinary approaches including biomaterials science, bioengineering, and cell biology expertise are used to generate a unique technology platform for tissue modeling and tissue engineering. The availability of such biofabricaton technology will directly allow for rapid scaffold design testing and better understanding of how biophysics and mechanics can drive ligament cell differentiation. Finally, this research program may open up avenues to intellectual properties, commercialization and interactions with industry partners.