贻贝仿生的强韧自愈合水凝胶的制备与性质研究

发布时间：2018-01-07 09:36

本文关键词：贻贝仿生的强韧自愈合水凝胶的制备与性质研究　出处：《长春工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：基于动态作用的,具有可调控的力学行为特性的水凝胶材料,因其具有快速的自主愈合以及自修复行为,目前已被广泛应用于组织工程和生物工程。因此,近年来,相关研究日趋成为研究热点。然而,通常情况下,水凝胶的机械行为和流变行为等力学性能同自愈合性能之间存在冲突,往往使得研究者在两者之间只能选择其一。因此,开发具有自愈合特性且力学行为良好的水凝胶材料成为目前这一研究领域最紧迫最前沿的突破点。水生生物贻贝,依靠其体内含有的多巴胺(Dopa)来提供在多种表面上强大的附着能力。在基于贻贝的多巴胺基仿生水凝胶当中,由于多巴胺上的酚羟基和Fe3+离子之间存在着强的络合作用,因而多巴胺基水凝胶具有优异的自愈合能力。然而这类水凝胶由于力学性能较差而难以在实际中得到应用。为了制备强韧的自愈合水凝胶,我们向含有Dopa的水凝胶网络中引入了不同的能量耗散机制,显著的提高了其力学性能的同时也保持了Dopa自身的特性,从而实现了水凝胶的功能化。首先,利用Dopa-Fe3+络合物与疏水缔合作用相协同,制备了具有快速无痕自愈合特性且具有一定力学性能的水凝胶。这种水凝胶在破裂后10 min内即可完全修复至初始状态,且断裂应力和断裂伸长率分别为30 kPa和2000%。此外,Dopa-Fe3+络合物的络合计量数具有pH依赖性,疏水缔合作用具有温度依赖性,这些特点赋予该水凝胶具备pH和温度的双重响应特性。同时,该水凝胶可以与金属铝表面形成氢键作用,使得水凝胶和铝表面之间的粘结力可达70 N·m-1。其次,制备了多巴胺基的杂化双网络水凝胶,以琼脂为第一网络,聚丙烯酰胺(PAAm)与Dopa共聚物作为第二网络。第一网络以琼脂网络之间的氢键作为交联点,第二网络以Dopa-Fe3+作为物理交联点,以N,N'-亚甲基双丙烯酰胺作为化学交联点。在应力作用时,第一网络首先破碎,将能量耗散,而第二网络内的可逆交联点会发生破坏-重组的过程,同时化学交联点会对水凝胶的整体网络起到一定的支撑作用。这样既我们制备的Agar/PAAm-Dopa-Fe3+DN水凝胶可同时具有良好的自愈合性质和良好的机械性能。当压缩形变为85%时,压缩应力可达到2.5 MPa。我们相信对具有自愈合性质的水凝胶进行增韧,可拓宽水凝胶在生物组织工程的应用。
[Abstract]:Hydrogel materials based on dynamic action with controllable mechanical behavior have been widely used in tissue engineering and bioengineering because of their rapid self-healing and self-repair behavior. In recent years, the related research has become a hot topic. However, in general, there is a conflict between mechanical behavior and rheological behavior of hydrogels and self-healing properties. Often, researchers have to choose between the two. The development of hydrogel materials with self-healing properties and good mechanical behavior has become the most urgent and most cutting-edge breakthrough point in this field. It relies on dopamine Dopaa, contained in the body, to provide strong adhesion on a variety of surfaces, in mussel based dopamine-based bionic hydrogels. There is a strong complexation between phenolic hydroxyl groups and Fe3 ions in dopamine. Therefore, dopamine-based hydrogels have excellent self-healing ability. However, these hydrogels are difficult to be applied in practice because of their poor mechanical properties. We introduce different energy dissipation mechanisms into the hydrogel network with Dopa, which can improve the mechanical properties of the hydrogel network and maintain the characteristics of Dopa itself. In order to realize the functionalization of hydrogels. Firstly, the Dopa-Fe3 complex and hydrophobic association were used to coordinate the hydrophobic association. A hydrogel with rapid self-healing and mechanical properties was prepared, which could be completely repaired to the initial state within 10 min after rupture. The breaking stress and elongation at break are 30 kPa and 2000, respectively. In addition, the complexometric number of Dopa-Fe _ 3 complex is pH dependent, and the hydrophobic association is temperature-dependent. These characteristics give the hydrogel a double response to pH and temperature. At the same time, the hydrogel can form a hydrogen bond with the metal aluminum surface. The adhesion between hydrogel and aluminum surface was 70 N 路m ~ (-1). Secondly, dopamine-based hybrid double-network hydrogels were prepared, with Agar as the first network. The first network uses the hydrogen bond between Agar network as the crosslinking point and the second network with Dopa-Fe3 as the physical crosslinking point. When the stress is applied, the first network breaks up first, the energy is dissipated, and the reversible crosslinking point in the second network will be destroyed and recombined. At the same time, the chemical crosslinking point will support the whole network of hydrogel, which is the Agar/PAAm-Dopa-Fe3 that we prepared. DN hydrogels have good self-healing properties and good mechanical properties at the same time. The compression stress can reach 2.5 MPA. We believe that the toughening of hydrogels with self-healing properties can broaden the application of hydrogels in biological tissue engineering.
【学位授予单位】：长春工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O648.17

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