Kiratitanaporn Wisarut, Guan Jiaao, Tang Min, Xiang Yi, Lu Ting-Yu, Balayan Alis, Lao Alison, Berry David B, Chen Shaochen
Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA.
Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, 92093, USA.
Biomater Sci. 2024 Nov 19;12(23):6047-6062. doi: 10.1039/d4bm00892h.
The myotendinous junction (MTJ) facilitates force transmission between muscle and tendon to produce joint movement. The complex microarchitecture and regional mechanical heterogeneity of the myotendinous junction pose major challenges in creating this interface . Engineering this junction is challenging due to substantial fabrication difficulties in creating scaffolds with intricate microarchitecture and stiffness heterogeneity to mimic the native muscle-tendon interface. To address the current challenges in creating the MTJ , digital light processing (DLP)-based 3D printing was used to fabricate poly(glycerol sebacate)acrylate (PGSA)-based muscle-tendon scaffolds with physiologically informed microstructure and mechanical properties. Local mechanical properties in various regions of the scaffold were tuned by adjusting the exposure time and light intensity used during the continuous DLP-based 3D printing process to match the mechanical properties present in distinct regions of native muscle-tendon tissue using printing parameters defined by an artificial intelligence-trained algorithm. To evaluate how the presence of zonal stiffness regions can affect the phenotype of a 3D-printed MTJ model, three 3D-printed PGSA-based scaffold conditions were investigated: (1) a scaffold with muscle-informed mechanical properties in its entirety without zonal stiffness regions, (2) a scaffold with one end possessing native muscle stiffness and the other end possessing native tendon stiffness, and (3) a scaffold with three distinct regions whose stiffness values correspond to those of muscle on one end of the scaffold, MTJ in the middle junction of the scaffold, and tendon on the other end of the scaffold. The scaffold containing regional mechanical heterogeneity most similar to the native MTJ (condition 3) was found to enhance the expression of MTJ-related markers compared to those without the presence of zonal stiffness regions. Overall, the DLP-based 3D printing platform and biomaterial system developed in this study could serve as a useful tool for mimicking the complexity of the native MTJ, which possesses inherent geometric and mechanical heterogeneity.
肌-腱连接(MTJ)促进肌肉与肌腱之间的力传递以产生关节运动。肌-腱连接复杂的微观结构和区域力学异质性给创建这个界面带来了重大挑战。由于在制造具有复杂微观结构和刚度异质性以模拟天然肌肉-肌腱界面的支架时存在巨大的制造困难,设计这个连接具有挑战性。为了解决当前创建MTJ的挑战,基于数字光处理(DLP)的3D打印被用于制造具有生理信息微观结构和力学性能的聚(癸二酸甘油酯)丙烯酸酯(PGSA)基肌肉-肌腱支架。通过调整基于连续DLP的3D打印过程中使用的曝光时间和光强度,来调节支架各个区域的局部力学性能,以匹配天然肌肉-肌腱组织不同区域的力学性能,使用的打印参数由人工智能训练算法定义。为了评估区域刚度区域的存在如何影响3D打印的MTJ模型的表型,研究了三种基于3D打印的PGSA支架条件:(1)一个整体具有肌肉信息力学性能且无区域刚度区域的支架;(2)一个一端具有天然肌肉刚度而另一端具有天然肌腱刚度的支架;(3)一个具有三个不同区域的支架,其刚度值分别对应于支架一端的肌肉、支架中间连接部位的MTJ以及支架另一端的肌腱。与没有区域刚度区域的支架相比,发现包含与天然MTJ最相似的区域力学异质性的支架(条件3)可增强MTJ相关标志物的表达。总体而言,本研究中开发的基于DLP的3D打印平台和生物材料系统可作为模拟天然MTJ复杂性的有用工具,天然MTJ具有固有的几何和力学异质性。
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