Purdue University, Weldon School of Biomedical Engineering, West Lafayette, IN, USA.
Acta Biomater. 2011 Dec;7(12):4139-48. doi: 10.1016/j.actbio.2011.07.023. Epub 2011 Jul 30.
The structures and mechanical properties of both physically and covalently cross-linked nanocomposite hydrogels made from poly(ethylene glycol) (PEG) and silicate nanoparticles (Laponite RD) are investigated. Injectable nanocomposite precursor solutions can be covalently cross-linked via photopolymerization. The resulting hydrogels are transparent and have interconnected pores, high elongation and toughness. These properties depend on the hydrogel composition, polymer-nanoparticle interactions and degree of cross-linking (both physical and covalent). Covalent cross-linking of polymer chains leads to the formation of an elastic network, whereas physical cross-linking between nanoparticles and polymer chains induces viscoelastic properties. At high deformations covalent bonds may be broken but physical bonds rebuild and to some extent self-heal the overall network structure. Addition of silicate also enhances the bioactivity and adhesiveness of the hydrogel as these materials stick to soft tissue as well as to hard surfaces. In addition, MC3T3-E1 mouse preosteoblast cells readily adhere and spread on nanocomposite hydrogel surfaces. Collectively, the combinations of properties such as elasticity, stiffness, interconnected network, adhesiveness to surfaces and bio-adhesion to cells provide inspiration and opportunities to engineer mechanically strong and elastic tissue matrixes for orthopedic, craniofacial and dental applications.
研究了由聚乙二醇（PEG）和硅酸盐纳米颗粒（Laponite RD）制成的物理和共价交联纳米复合水凝胶的结构和力学性能。可注射的纳米复合前体溶液可通过光聚合进行共价交联。所得水凝胶透明，具有相互连接的孔，具有高伸长率和韧性。这些性能取决于水凝胶的组成、聚合物-纳米颗粒相互作用和交联程度（物理和共价）。聚合物链的共价交联导致形成弹性网络，而纳米颗粒和聚合物链之间的物理交联则诱导粘弹性。在高变形下，共价键可能会断裂，但物理键会重建，并在一定程度上自我修复整个网络结构。添加硅酸盐还可以增强水凝胶的生物活性和粘附性，因为这些材料会粘接到软组织以及硬表面上。此外，MC3T3-E1 小鼠前成骨细胞很容易在纳米复合水凝胶表面附着和展开。总的来说，弹性、刚度、相互连接的网络、对表面的粘附性以及对细胞的生物粘附性等特性的结合，为工程骨科、颅面和牙科应用中的机械强度高且弹性强的组织基质提供了灵感和机会。
