Nedrelow David S, Detamore Michael S
Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, OK, USA.
College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
Ann Biomed Eng. 2025 Jul 11. doi: 10.1007/s10439-025-03791-2.
The cartilaginous surfaces in ginglymus (hinge) joints such as the knee, elbow, and the ginglymoarthrodial temporomandibular joint (TMJ) primarily function under unidirectional shear and orthogonal compression. Regenerative medicine approaches to treat injured or arthritic joints include biphasic scaffolds, which must withstand the joint's biomechanical demands. In the current study, we leveraged computational modeling to design a 3D-printed biphasic scaffold with enhanced biomechanical performance for ginglymus joints. A sinusoidal hourglass tube geometry was introduced to support shear stresses at the hydrogel-substrate interface and to support orthogonal compression. Biphasic constructs were evaluated with both empirical and in silico interface shear experiments. A thermal extrusion 3D-printed polylactic acid (PLA) hourglass interface was infilled with a hydrogel, comprised of either (1) agarose or (2) pentenoate-modified hyaluronic acid (PHA), polyethylene glycol diacrylate (PEGDA), and devitalized cartilage (DVC). Shear loads were applied either parallel to the tube's long axis (i.e., 1-direction) or orthogonally (i.e., 2-direction). Additionally, the hourglass tube architecture without any hydrogel was evaluated in compression in the 1- and 3-directions. Empirically, ultimate interface shear stresses up to 51 ± 7 kPa were observed for the infilled PHA-PEGDA-DVC hydrogels, with higher values in both loading directions compared to a crosshatch scaffold as a standard-of-comparison control (p < 0.05). The computer model suggested a geometry-dependent shear load transfer. The ultimate compressive stress for the hourglass architecture in the 3-direction reached 6.9 ± 1.8 MPa, which was 39% higher than the crosshatch architecture. The hourglass design enhanced performance under shear in the 1-direction and compression in the 3-direction, which may add value for future designs employed for regenerating tissues in ginglymus joints that primarily function under unidirectional shear and orthogonal compression.
膝关节、肘关节等屈戌关节（铰链关节）以及颞下颌关节（TMJ）的软骨表面主要在单向剪切力和正交压缩力作用下发挥功能。治疗受伤或患有关节炎关节的再生医学方法包括双相支架，这种支架必须能够承受关节的生物力学需求。在当前研究中，我们利用计算建模设计了一种用于屈戌关节的、具有增强生物力学性能的3D打印双相支架。引入正弦沙漏管几何结构以支撑水凝胶-基质界面处的剪切应力并承受正交压缩力。通过实验和计算机模拟界面剪切实验对双相结构进行评估。一个热挤压3D打印的聚乳酸（PLA）沙漏界面填充有水凝胶，该水凝胶由以下两种成分之一组成：（1）琼脂糖，或（2）戊烯酸酯改性透明质酸（PHA）、聚乙二醇二丙烯酸酯（PEGDA）和失活软骨（DVC）。剪切载荷平行于管的长轴（即1方向）或正交方向（即2方向）施加。此外，对没有任何水凝胶的沙漏管结构在1方向和3方向进行压缩评估。通过实验观察到，填充PHA-PEGDA-DVC水凝胶的极限界面剪切应力高达51±7 kPa，与作为比较标准对照的交叉网格支架相比，在两个加载方向上的值都更高（p < 0.05）。计算机模型表明存在与几何形状相关的剪切载荷传递。沙漏结构在3方向的极限压缩应力达到6.9±1.8 MPa，比交叉网格结构高39%。沙漏设计增强了在1方向的剪切和3方向的压缩下的性能，这可能为未来用于再生主要在单向剪切和正交压缩下发挥功能的屈戌关节组织的设计增加价值。
