The biodegradable cardiac patch is desirable to possess mechanical properties mimicking native myocardium for heart infarction treatment. We fabricated a series of anisotropic and biodegradable polyurethane porous scaffolds via thermally induced phase separation (TIPS) and tailored their mechanical properties by using various polyurethanes with different soft segments and varying polymer concentrations. The uniaxial mechanical properties, suture retention strength, ball-burst strength, and biaxial mechanical properties of the anisotropic porous scaffolds were optimized to mechanically match native myocardium. The optimal anisotropic scaffold had a ball burst strength (20.7 ± 1.5 N) comparable to that of native porcine myocardium (20.4 ± 6.0 N) and showed anisotropic behavior close to biaxial stretching behavior of the native porcine myocardium. Furthermore, the optimized porous scaffold was combined with a porcine myocardium-derived hydrogel to form a biohybrid scaffold. The biohybrid scaffold showed morphologies similar to the decellularized porcine myocardial matrix. This combination did not affect the mechanical properties of the synthetic scaffold alone. After in vivo rat subcutaneous implantation, the biohybrid scaffolds showed minimal immune response and exhibited higher cell penetration than the polyurethane scaffold alone. This biohybrid scaffold with biomimetic mechanics and good tissue compatibility would have great potential to be applied as a biodegradable acellular cardiac patch for myocardial infarction treatment.

中文翻译：

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优化各向异性聚氨酯支架以与天然心肌机械匹配

理想的是，可生物降解的心脏贴剂具有模仿天然心肌的机械性能，用于心脏梗塞治疗。我们通过热诱导相分离（TIPS）制造了一系列各向异性且可生物降解的聚氨酯多孔支架，并通过使用具有不同软链段和不同聚合物浓度的各种聚氨酯来调整其机械性能。各向异性多孔支架的单轴力学性能，缝合线保持强度，球爆强度和双轴力学性能均经过优化以与天然心肌机械匹配。最佳的各向异性支架具有与天然猪心肌（20.4±6.0 N）相当的球形破裂强度（20.7±1.5 N），并且显示出接近于天然猪心肌的双轴拉伸行为的各向异性行为。此外，将优化的多孔支架与猪心肌来源的水凝胶结合以形成生物杂交支架。生物杂交支架显示出类似于脱细胞猪心肌基质的形态。该组合不影响单独的合成支架的机械性能。后在体内大鼠皮下植入中，生物混合支架比单独的聚氨酯支架表现出最小的免疫反应并表现出更高的细胞渗透性。这种具有仿生机制和良好组织相容性的生物杂种支架将具有巨大的潜力，可作为可生物降解的脱细胞心脏贴剂用于心肌梗塞治疗。