Department of Mechanical Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Department of Mechanical Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Acta Biomater. 2018 Apr 1;70:98-109. doi: 10.1016/j.actbio.2018.02.003. Epub 2018 Feb 12.
Well-organized composite formations such as hierarchical nested-network (NN) structure in bone tissue and reticular connective tissue present remarkable mechanical strength and play a crucial role in achieving physical and biological functions for living organisms. Inspired by these delicate microstructures in nature, an analogous scaffold of double network hydrogel was fabricated by creating a poly(2-hydroxyethyl methacrylate) (pHEMA) network in the porous structure of alginate hydrogels. The resulting hydrogel possessed hierarchical NN structure and showed significantly improved mechanical strength but still maintained high elasticity comparable to soft tissues due to a mutual strengthening effect between the two networks. The tough hydrogel is also self-lubricated, exhibiting a surface friction coefficient comparable with polydimethylsiloxane (PDMS) substrates lubricated by a commercial aqueous lubricant (K-Y Jelly) and other low surface friction hydrogels. Additional properties of this hydrogel include high hydrophilicity, good biocompatibility, tunable cell adhesion and bacterial resistance after incorporation of silver nanoparticles. Firm bonding of the hydrogel on silicone substrates could be achieved through facile chemical modification, thus enabling the use of this hydrogel as a versatile coating material for biomedical applications.
In this study, we developed a tough hydrogel by crosslinking HEMA monomers in alginate hydrogels and forming a well-organized structure of hierarchical nested network (NN). Different from most reported stretchable alginate-based hydrogels, the NN hydrogel shows higher compressive strength but retains comparable softness to alginate counterparts. This work further demonstrated the good integration of the tough hydrogel with silicone substrates through chemical modification and micropillar structures. Other properties including surface friction, biocompatibility and bacterial resistance were investigated and the hydrogel shows a great promise as a versatile coating material for biomedical applications.
组织有序的复合结构，如骨组织和网状结缔组织中的分级嵌套网络（NN）结构，具有显著的机械强度，对实现生物体的物理和生物功能起着至关重要的作用。受自然界中这些精细微观结构的启发，通过在藻酸盐水凝胶的多孔结构中创建聚（2-羟乙基甲基丙烯酸酯）（pHEMA）网络，制备了类似的双网络水凝胶支架。所得水凝胶具有分级 NN 结构，机械强度显著提高，但由于两个网络之间的相互增强作用，仍保持与软组织相当的高弹性。由于两个网络之间的相互增强作用，坚韧的水凝胶也具有自润滑性，其表面摩擦系数可与经商业水基润滑剂（K-Y 润滑剂）和其他低表面摩擦水凝胶润滑的聚二甲基硅氧烷（PDMS）基底相媲美。该水凝胶还具有高亲水性、良好的生物相容性、经银纳米粒子掺入后可调节的细胞黏附性和抗细菌能力等额外特性。通过简单的化学修饰可以实现水凝胶在硅酮基底上的牢固结合，从而使该水凝胶能够作为一种多功能的涂层材料用于生物医学应用。
在这项研究中，我们通过将 HEMA 单体交联到藻酸盐水凝胶中并形成分级嵌套网络（NN）的有序结构，开发了一种坚韧的水凝胶。与大多数报道的可拉伸藻酸盐基水凝胶不同，NN 水凝胶具有更高的压缩强度，但仍保持与藻酸盐对应物相当的柔软度。这项工作进一步通过化学修饰和微柱结构展示了坚韧水凝胶与硅酮基底的良好集成。还研究了其他特性，包括表面摩擦、生物相容性和抗细菌能力，水凝胶作为生物医学应用的多功能涂层材料具有很大的应用前景。
