Zhou Yang, Cui Yuecheng, Wang Li-Qun
MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
Hangzhou Medsun Biological Technology Co., Ltd, Hangzhou Economic and Technological Development Area, Hangzhou 310027, P. R. China.
Int J Bioprint. 2021 Jun 29;7(3):389. doi: 10.18063/ijb.v7i3.389. eCollection 2021.
The thermo-sensitive hydrogel formed by triblock copolymers of polyethylene glycols and aliphatic polyesters serves as a promising candidate for bioink due to its excellent biodegradability and biocompatibility. However, the thermo-crosslinking alone cannot achieve a robust hydrogel to support the 3D printed constructs without collapse. Herein, a photo-crosslinkable group was introduced into the triblock copolymers to achieve a dual-sensitive hydrogel. A triblock copolymer poly(lactide-co-glycolide)-polyethylene glycol-poly(lactide-co-glycolide) decorated with acrylate group in the chain end was prepared. The obtained aqueous solutions of the copolymers could transform into hydrogels with excellent shear thinning properties and rapid elastic recovery properties spontaneously on the increase of temperature. The resulted thermogels also allowed for photo-crosslinking by exposure to ultraviolet radiation, with storage modulus dramatically increased to stable the printed constructs. Through a two-step crosslinking strategy, complicated tissue-like constructs with high shape fidelity can be printed using the dual-sensitive inks. Moreover, the mechanical strength, swelling ratio, and printability of the hydrogels can be tuned by varying the substitution rate of the acrylate group without compromising the inks' extrudability. We expect that the dual-sensitive hydrogels may be used as bioinks to print large constructs for applications in tissue engineering.
由聚乙二醇和脂肪族聚酯的三嵌段共聚物形成的热敏水凝胶，因其优异的生物降解性和生物相容性，成为生物墨水的一个有前景的候选材料。然而，仅靠热交联无法获得坚固的水凝胶来支撑3D打印结构而不塌陷。在此，将可光交联基团引入三嵌段共聚物中，以获得双敏水凝胶。制备了一种在链端带有丙烯酸酯基团的三嵌段共聚物聚（丙交酯-乙交酯）-聚乙二醇-聚（丙交酯-乙交酯）。所得到的共聚物水溶液在温度升高时可自发转变为具有优异剪切变稀性能和快速弹性恢复性能的水凝胶。所得的热凝胶也可通过紫外线照射进行光交联，其储能模量显著增加，从而稳定打印结构。通过两步交联策略，使用双敏墨水可以打印出具有高形状保真度的复杂组织样结构。此外，通过改变丙烯酸酯基团的取代率，可以调节水凝胶的机械强度、溶胀率和可打印性，而不影响墨水的挤出性。我们期望双敏水凝胶可用作生物墨水来打印大型结构，用于组织工程应用。
