The freeze-drying is a technology that preserves biological samples in a dry state, which is beneficial for storage, transportation, and cost saving. In this study, the bovine pericardium was treated with a freeze-drying protectant composed of polyethylene glycol (PEG) and trehalose (Tre), and then freeze-dried. The results demonstrated that the mechanical properties of the pericardium treated with PEG + 10% w/v Tre were superior to those of the pericardium fixed with glutaraldehyde (GA). The wet state water content of the rehydrated pericardium, determined using the Karl Fischer method, was (74.81 ± 1.44)%, which was comparable to that of the GA-fixed pericardium. The dry state water content was significantly reduced to (8.64 ± 1.52)%, indicating effective dehydration during the freeze-drying process. Differential scanning calorimetry (DSC) testing revealed that the thermal shrinkage temperature of the pericardium was (84.96 ± 0.49) ℃, higher than that of the GA-fixed pericardium (83.14 ± 0.11) ℃, indicating greater thermal stability. Fourier transform infrared spectroscopy (FTIR) results showed no damage to the protein structure during freeze-drying. Hematoxylin and eosin (HE) staining demonstrated that the freeze-drying process reduced pore formation, prevented ice crystal growth, and resulted in a tighter arrangement of tissue fibers. The frozen-dried bovine pericardium was subjected to tests for cell viability and hemolysis rate. The results revealed a cell proliferation rate of (77.87 ± 0.49)%, corresponding to a toxicity grade of 1. Additionally, the hemolysis rate was (0.17 ± 0.02)%, which is below the standard of 5%. These findings indicated that the frozen-dried bovine pericardium exhibited satisfactory performance in terms of cytotoxicity and hemolysis, thus meeting the relevant standards. In summary, the performance of the bovine pericardium treated with PEG + 10% w/v Tre and subjected to freeze-drying could meet the required standards.
冷冻干燥是一种使生物样本在干燥状态下保存的技术，有利于储存、运输并节省成本。本文使用聚乙二醇（PEG）和海藻糖（Tre）组成的冻干保护剂处理牛心包，进行冷冻干燥。结果表明：使用PEG + 10% w/v Tre处理牛心包进行冷冻干燥后，其力学性能优于使用戊二醛（GA）固定的牛心包。卡尔费休法测定，牛心包复水后的湿态含水量为（74.81 ± 1.44）%，与GA固定的牛心包无明显差异。干态含水量为（8.64 ± 1.52）%，说明在冷冻干燥过程中能有效脱水。差示扫描量热仪（DSC）的测试结果显示，牛心包的热皱缩温度为（84.96 ± 0.49）℃比GA固定的牛心包（83.14 ± 0.11）℃高，说明具有更高的热稳定性。傅里叶变换红外光谱（FTIR）结果显示，在冷冻干燥过程中，蛋白质结构并未受到破坏。苏木精-伊红（HE）染色表明，冷冻干燥过程可以减少孔隙的产生，防止冰晶的生长，使组织纤维结构排列更紧密。细胞存活率与溶血率检测结果显示，细胞增殖率为（77.87 ± 0.49）%，毒性分级为1级，溶血率为（0.17 ± 0.02）%，低于5%的标准，即经过冷冻干燥处理的牛心包在细胞毒性和溶血方面表现良好，符合相关标准。综上，使用PEG + 10% w/v Tre处理牛心包进行冷冻干燥后的性能符合要求。.
Keywords: Freeze drying; Mechanical property; Polyethylene glycol; Thermal shrinkage temperature; Trehalose.