【作者】 胡静；

【导师】 张艳；

【作者基本信息】 南京大学 ， 化学、有机化学， 2016， 硕士

【摘要】 由小分子通过非共价的分子间相互作用自组装形成的超分子水凝胶是近年来较受关注的构建智能响应型生物功能材料的一种有效方法。将具有平面共轭结构的疏水分子修饰在合成短肽或其它可形成分子间氢键作用的生物活性分子上已被证实是促进这些分子发生自组装的有效方法,而其中能够在生物相容条件下形成超分子水凝胶的体系则有可能被用于构建生物功能材料。本论文在修饰了平面共轭型分子的单糖及糖胺分子在中性水溶液中发生自组装形成超分子水凝胶的体系方面开展了研究,发现了将平面开环型的吲哚啉螺吡喃分子通过合适的方法与单糖或糖胺分子相连后,可大大促进这类分子在中性水溶液中发生自组装形成超分子水凝胶的能力,由此类吲哚啉螺吡喃修饰的单糖或糖胺分子自组装形成的水凝胶对可见光照具有较为灵敏的响应性质,我们进而对这类光响应型超分子水凝胶在细胞培养及生物功能分子的可控释放和传输方面的应用进行了探索。论文工作主要分为两部分,首先是通过化学合成获取了一系列由平面共轭基团修饰的单糖分子或糖胺分子并对它们在中性水溶液中的自组装性质的研究。我们选择了三种具有平面共轭结构的结构单元,也即开环型的吲哚啉螺吡喃(MC),二芳基四氮唑(Tet)及萘环(Nap),通过一个甘氨酸作为连接基团将它们分别连接在D-葡萄糖胺(Ⅰ)和1-O-氨基-β-D-吡喃半乳糖(Ⅱ)得到了MC-Ⅰ,MC-Ⅱ, Tet-Ⅰ, Tet-Ⅱ, Nap-Ⅰ, Nap-Ⅱ这六种小分子并对其结构进行了表征。中性水溶液中的成胶性能测试表明这六种分子中仅MC-Ⅰ和MC-Ⅱ具有形成超分子水凝胶的性能,显示平面共轭的吲哚啉螺吡喃分子对于糖类分子的自组装具有很好的促进作用。由于平面型的吲哚啉螺吡喃分子(MC)在可见光的照射下可迅速转变为相应的螺环结构(SP),因此通过光照诱导带有MC取代基团的凝胶因子的结构转换,进而实现超分子水凝胶的光响应。论文第二部分工作主要对MC-Ⅰ及MC-Ⅱ形成的超分子水凝胶在光照下的响应进行了研究,并基于这类生物相容性的光敏超分子水凝胶发展了培养在凝胶表面的细胞内可控传输蛋白及微小核糖核酸的生物功能材料体系。首先是利用MC-Ⅰ及MC-Ⅱ形成的超分子水凝胶包裹马血清蛋白,通过可见光照将包裹在超分子水凝胶中的马血清蛋白释放出来,进而诱导C2C12细胞分化,通过qRT-PCR检测细胞分化标记物的mRNA相对表达量。其次我们还将miRNA-122包裹在MC-Ⅰ及MC-Ⅱ形成的超分子水凝胶中,同样通过可见光照将包裹在超分子水凝胶中的miRNA-122释放出来,通过qRT-PCR检测培养在水凝胶表面的HepG2细胞中miRNA-122相对表达量。通过以上的实验,我们发现通过光诱导水凝胶的转变进而实现蛋白及微小核糖核酸的可控传输具有一定的可行性。下面我们会对实验做进一步的探索和优化。更多还原

【Abstract】 Supramolecular hydrogel formed by the self-assembly of low-molecular weight hydrogelator through noncovalent interaction has recently emerged as "smart" biomaterial for dieverse biological applications. After conjugation with short peptides or other bioactive molecules that can form intermolecular hydrogen bonds, hydrophobic molecules with plane conjugated structure have been shown as efficient scaffolds to promote their self-assembly in aqeous solution. Addtionally, supramolecular hydrogel that could form under biocompatible conditions may serve as novel biomaterial. In this thesis, we focused on the construction of suprmoalecular hydrogel fromed by glucosamine and galactopyranose that were modified with hydrophobic molecules with plane conjugated structure. We found ring-opened spiropyran could promote the self-assembly of glucosamine and galactopyranose in neutral aqueous solution after appropriate conjugation. The formed supramolecular hydrogel was sensitive to visible light and we next explored their application in cell culture and controlled release of biomolecules.The first part of this thesis focused on the synthesis of hydrogelators that consisted of glucosamine/galactopyranose and hydrophobic molecules and on the study of their self-assembly in neutral aqueous solution. Three hydrophobic molecules with plane conjugated structure were selected, inlucding ring-opened spiropyran (MC), diaryl-tetrazole (Tet), and naphthalene (Nap). Using glycine as the linker, we modidied them with D-glucosamine (I) and amino-1-O-β-D-galactopyranose (Ⅱ). Six small molecules, MC-Ⅰ,MC-Ⅱ, Tet-Ⅰ, Tet-Ⅱ, Nap-Ⅰ and Nap-Ⅱ, were then obtained and characterized prior to further investigations. Hydrogelation test in neutral aqueous solution showed that only MC-Ⅰ and MC-Ⅱ could form hydrogel, indicating plane-conjugated spiropyran could promote self-assembly of saccharides. Since merocyanine (MC) can be quickly converted into the corresponding spiropyran (SP) under visible light irradiation, the formed supramolecular hydrogel could respond to light through the structure change between MC and SP.The second part of this thesis focused on the photo response of supramolecular hydrogel formed by MC-Ⅰ and MC-Ⅱ and their subsequent applications in controlled delivery of bioactive molecules into cells cultured on top of gel. Horse serum was entrapped inside the gel formed by MC-Ⅰ and MC-Ⅱ and was delivered into C2C12 cells to promote differentiation upon light irradiation, which were further characterized by measuring the expression level of differentiation markers by quantitative real-time PCR. Similarly, miR-122 was also trapped in the gel formed by MC-Ⅰ and MC-Ⅱ. Upon light irradiation, miR-122 was released from the gel and delivered into HepG2 cells cultured on the top of hydrogel, which were demonstrated by measuring the expression level of endogenous miR-122 by quantitative real-time PCR. Through the applications described above, we found MC-Ⅰ and MC-Ⅱ were potential smart biomaterials for controlled delivery of protein and miRNA through light irradiation. Further optimization and exploration are still underway in our group.更多还原