Mechanical properties of L-lysine based segmented polyurethane vascular grafts and their shape memory potential
Mechanical properties of L-lysine based segmented polyurethane vascular grafts and their shape memory potential
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DOI：
10.1016/j.msec.2019.04.073
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发表时间：
2019-09-01
影响因子：
7.9
通讯作者：
Peponi, L.
中科院分区：
文献类型：
--
作者：
Castillo-Cruz, O.;Aviles, F.;Peponi, L.
合成了以聚己内酯、4，4(亚甲基双环己基)异氰酸酯和L赖氨酸为基础的嵌段聚氨酯，制成了小血管移植物，并按照ISO7198心血管植入管状血管假体标准进行了表征。在力学性能方面，新合成的聚氨酯薄膜的割线模数低于著名的医用级聚氨酯Tecoflex(TM)SG 80A。同样，与Tecoflex(商标)SG 80A移植物相比，以L赖氨酸为基础的聚氨酯移植物的纵向破坏载荷(11.5N比116N)、单位长度的环向破坏载荷(5.67N/mm比14.0N/mm)以及尼龙(13.3N比24.0N)和丝绸(14.0N比19.3N)的缝合力都更低。L-赖氨酸基移植物的破裂强度为3620毫米汞柱(482.6千帕)，柔顺性为0.16%/毫米汞。在NIH/3T3成纤维细胞上观察到细胞黏附，在薄膜和移植物上都观察到细胞黏附，而只有在移植物上观察到细胞排列。这种聚氨酯的力学性能和应变诱导PCL晶体作为形状记忆材料的开关相的可能性，使应变恢复率和应变固定率分别高于95%和90%，形状记忆性能的重复性可达4次热机械循环。总体而言，赖氨酸基聚氨酯的性能适合于大直径血管移植物，其中细胞的排列可以通过其形状记忆潜力来控制。
Segmented polyurethanes based on polycaprolactone, 4,4 (metylene-bis-cyclohexyl) isocyanate, and L-lysine were synthesized, manufactured as small vascular grafts and characterized according to ISO 7198 standard for cardiovascular implants-tubular vascular prosthesis. In terms of mechanical properties, the newly synthesized polyurethane films exhibited lower secant modulus than Tecoflex (TM) SG 80A, a well-known medical grade polyurethane. Similarly, when tested as grafts, the L-lysine-based polyurethane exhibited lower longitudinal failure load (11.5 N vs. 116 N), lower circumferential failure load per unit length (5.67 N/mm vs. 14.0 N/mm) and lower suture forces for both nylon (13.3 N vs. 24.0 N) and silk (14.0 N vs. 19.3 N) when compared to Tecoflex (TM) SG 80A grafts. L-Lysine-based graft exhibited a burst strength of 3620 mmHg (482.6 kPa) and a compliance of 0.16%/mmHg. The cell adhesion was demonstrated with NIH/3T3 fibroblasts where cell adhesion was observed on both films and grafts, while cell alignment was observed only on the grafts. The mechanical properties of this polyurethane and the possibility of strain-induced PCL crystals as the switching phase for shape memory materials, allowed a strain recovery ratio and a strain fixity ratio with values higher than 95% and 90%, respectively, with a repeatability of the shape-memory properties up to 4 thermo-mechanical cycles. Overall, the properties of lysine-based polyurethanes are suitable for large diameter vascular grafts where cell alignment can be controlled by their shape memory potential.