摘要：家蚕蚕丝中包含大量丝素纤维，将丝素纤维溶解提纯后获得的丝素蛋白可以运用 在食品、化妆品、生物医药等多个领域。但是不经过交联反应的丝素蛋白由于机械性 能较差和水溶失率大而在实际生产中的应用受到限制。经过国内外科研人员的研究， 人们可以通过物理和化学的方法使丝素蛋白相互交联使其能够真正应用于生活中。

丝素蛋白光引发交联的方法相对于物理或者化学交联有着反应速度快，耗能低， 污染小等优点。本文我们研究了使用廉价的维生素 B2 引发丝素蛋白光交联的方法和 探索最优化的实验条件。通过考察交联后丝素蛋白的吸水性，利用傅里叶变换红外光 谱（FTIR）、X 射线衍射（XRD）、场致发生电子扫描电镜（SEM）、荧光图谱（FL） 等表征手段研究丝素蛋白交联情况、性能和结构。我们发现交联后的丝素蛋白吸水率 达到了 96.07%，吸水后的质量可以达到吸水前的 25.63 倍，可见交联后的丝素蛋白具 有极强的吸水性和保水性，这个结果不仅与丝素的性质有关，而且与其规则的三维多 孔结构有着密切的关系。另外，我们利用荧光图谱表征了交联后的丝素蛋白的荧光发 射峰，相较于未处理的丝素蛋白，其在 410 nm 处出现了一个新的发射峰，验证了维 生素 B2 的交联机理，即光激态的维生素 B2 引发丝素蛋白上酪氨酸交联形成二酪氨 酸复合体，最后我们利用 FTIR 和 XRD 表征光交联后丝素蛋白的性质和晶体结构， 表明通过该方法可以成功制备交联的丝素蛋白，有望应用于细胞培养、组织工程、药 物运输等。

关键词：蚕丝；丝素蛋白；光交联；水凝胶；维生素 B2

Abstract：Silk contains a large number of silk fibroin fibers, the purified silk fibroin can be used in food, cosmetics, biomedicine and other related fields. Sometimes, the mechanical properties of silk fibroin are poor, and water loss rate is large, so it is difficult to apply to the actual application and production. In order to solve these problems, many researchers devote to the study of silk crosslinking gusing physical or chemical method for the purpose of practical application, but very few works focus on the photocrosslink of silk.

The light-excited crosslinking has a lot of advantages relative to the physical or chemical method, such as fast response, low energy consumption and non-pollution. Herein, the low-cost vitamin B2 was used to induce the crosslinking of silk fibroin with optimally experimental conditions. The properties and structure of crosslinked silk fibroin were studied by means of fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy (FL). Accordingly, we found that their water absorption was confirmed to reach upwards of 96.07%, the mass was about 25.63 times water absorption, which showed a strong water absorption and retention. The result was not  only closely related to their own properties, but also the formed regular 3D porous structure characterized by SEM. The mechanism was also studied by FL. Compared with the untreated silk fibroin, a new emission peak of 410 nm appeared in crosslinked silk fibroin, which proved the presence of dityrosine triggered by vitamin B2. At last, the synthesis of crosslinked silk fibroin was verified by their properties and crystal structure which were achieved through FTIR and XRD. This approach may provide a promising way to fabricate low-cost and nontoxic silk fibroin film, gel or bulk materials that will find wide application in tissue engineering and drug delivery.

Keywords：Silk; Silk fibroin; Photocrosslinking; Hydrogel; Vitamin B2

目录

第一章 绪 论 1

1.1  丝素蛋白的组成和结构