Güney Aysun, Gardiner Christina, McCormack Andrew, Malda Jos, Grijpma Dirk W
Department of Biomaterials Science and Technology, Science and Technology Faculty, Technical Medical Centre, University of Twente, 7500AE Enschede, The Netherlands.
Department of Orthopaedics, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands.
Bioengineering (Basel). 2018 Nov 14;5(4):99. doi: 10.3390/bioengineering5040099.
Novel tough hydrogel materials are required for 3D-printing applications. Here, a series of thermoplastic polyurethanes (TPUs) based on poly(ɛ-caprolactone)--poly(ethylene glycol)--poly(ɛ-caprolactone) (PCL--PEG--PCL) triblock copolymers and hexamethylene diisocyanate (HDI) were developed with PEG contents varying between 30 and 70 mol%. These showed excellent mechanical properties not only when dry, but also when hydrated: TPUs prepared from PCL--PEG--PCL with PEG of Mn 6 kg/mol (PCL₇-PEG₆-PCL₇) took up 122 wt.% upon hydration and had an E-modulus of 52 ± 10 MPa, a tensile strength of 17 ± 2 MPa, and a strain at break of 1553 ± 155% in the hydrated state. They had a fracture energy of 17976 ± 3011 N/mm² and a high tearing energy of 72 kJ/m². TPUs prepared using PEG with Mn of 10 kg/mol (PCL₅-PEG-PCL₅) took up 534% water and were more flexible. When wet, they had an E-modulus of 7 ± 2 MPa, a tensile strength of 4 ± 1 MPa, and a strain at break of 147 ± 41%. These hydrogels had a fracture energy of 513 ± 267 N/mm² and a tearing energy of 16 kJ/m². The latter TPU was first extruded into filaments and then processed into designed porous hydrogel structures by 3D-printing. These hydrogels can be used in 3D printing of tissue engineering scaffolds with high fracture toughness.
3D打印应用需要新型的坚韧水凝胶材料。在此，基于聚（ε-己内酯）-聚（乙二醇）-聚（ε-己内酯）（PCL-PEG-PCL）三嵌段共聚物和六亚甲基二异氰酸酯（HDI）开发了一系列热塑性聚氨酯（TPU），其中PEG含量在30至70摩尔％之间变化。这些材料不仅在干燥时表现出优异的机械性能，在水合时也是如此：由Mn为6 kg/mol的PEG的PCL-PEG-PCL制备的TPU（PCL₇-PEG₆-PCL₇）在水合时吸收122 wt.%的水，在水合状态下具有52±10 MPa的弹性模量、17±2 MPa的拉伸强度和1553±155%的断裂应变。它们具有17976±3011 N/mm²的断裂能和72 kJ/m²的高撕裂能。使用Mn为10 kg/mol的PEG制备的TPU（PCL₅-PEG-PCL₅）吸收534%的水且更具柔韧性。潮湿时，它们具有7±2 MPa的弹性模量、4±1 MPa的拉伸强度和147±41%的断裂应变。这些水凝胶具有513±267 N/mm²的断裂能和16 kJ/m²的撕裂能。后一种TPU首先被挤出成细丝，然后通过3D打印加工成设计好的多孔水凝胶结构。这些水凝胶可用于具有高断裂韧性的组织工程支架的3D打印。
