Department of Bioengineering, Rice University, Houston, TX, USA.
Acta Biomater. 2013 Mar;9(3):5630-42. doi: 10.1016/j.actbio.2012.10.032. Epub 2012 Nov 2.
A three-dimensional scaffold composed of self-assembled polycaprolactone (PCL) sandwiched in a gelatin-chitosan hydrogel was developed for use as a biodegradable patch with a potential for surgical reconstruction of congenital heart defects. The PCL core provides surgical handling, suturability and high initial tensile strength, while the gelatin-chitosan scaffold allows for cell attachment, with pore size and mechanical properties conducive to cardiomyocyte migration and function. The ultimate tensile stress of the PCL core, made from blends of 10, 46 and 80kDa (Mn) PCL, was controllable in the range of 2-4MPa, with lower average molecular weight PCL blends correlating with lower tensile stress. Blends with lower molecular weight PCL also had faster degradation (controllable from 0% to 7% weight loss in saline over 30 days) and larger pores. PCL scaffolds supporting a gelatin-chitosan emulsion gel showed no significant alteration in tensile stress, strain or tensile modulus. However, the compressive modulus of the composite tissue was similar to that of native tissue (∼15kPa for 50% gelatin and 50% chitosan). Electron microscopy revealed that the gelatin-chitosan gel had a three-dimensional porous structure, with a mean pore diameter of ∼80μm, showed migration of neonatal rat ventricular myocytes (NRVM), maintained NRVM viability for over 7 days, and resulted in spontaneously beating scaffolds. This multi-layered scaffold has sufficient tensile strength and surgical handling for use as a cardiac patch, while allowing migration or pre-loading of cardiac cells in a biomimetic environment to allow for eventual degradation of the patch and incorporation into native tissue.
一种由自组装聚己内酯（PCL）夹在明胶-壳聚糖水凝胶中的三维支架被开发出来，用作可生物降解的贴片，具有先天性心脏缺陷手术重建的潜力。PCL 核心提供手术处理、可缝合性和初始拉伸强度高，而明胶-壳聚糖支架允许细胞附着，具有有利于心肌细胞迁移和功能的孔径和机械性能。由 10、46 和 80kDa（Mn）PCL 混合制成的 PCL 芯的极限拉伸应力在 2-4MPa 的范围内是可控的，分子量较低的 PCL 混合与较低的拉伸应力相关。分子量较低的 PCL 混合也具有更快的降解（在 30 天内可控制从生理盐水的 0%到 7%的重量损失）和更大的孔。支撑明胶-壳聚糖乳液凝胶的 PCL 支架在拉伸应力、应变或拉伸模量方面没有明显变化。然而，复合组织的压缩模量与天然组织相似（50%明胶和 50%壳聚糖为∼15kPa）。电子显微镜显示，明胶-壳聚糖凝胶具有三维多孔结构，平均孔径约为 80μm，显示出新生大鼠心室肌细胞（NRVM）的迁移，维持 NRVM 活力超过 7 天，并导致自发搏动的支架。这种多层支架具有足够的拉伸强度和手术处理能力，可作为心脏贴片使用，同时允许在仿生环境中迁移或预加载心脏细胞，以实现贴片的最终降解并纳入天然组织。
