Preparation and Statistical Characterization of Tunable Porous Sponge Scaffolds using UV Cross-linking of Methacrylate-Modified Silk Fibroin
Preparation and Statistical Characterization of Tunable Porous Sponge Scaffolds using UV Cross-linking of Methacrylate-Modified Silk Fibroin
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DOI：
10.1021/acsbiomaterials.9b00814
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发表时间：
2019-12-01
影响因子：
5.8
通讯作者：
Motta, Antonella
中科院分区：
文献类型：
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作者：
Bucciarelli, Alessio;Muthukumar, Thangavelu;Motta, Antonella
丝素蛋白海绵在组织工程中的应用已经得到了广泛的研究和文献报道。多年来，已经提出了几种制造方法，以满足性质方面的大多数要求，这些要求应适应所考虑的组织。这些过程大多是基于蛋白质的二级结构转变到稳定的β晶体形式。这种转变，被称为物理交联，使海绵抵抗溶解在水中，一般来说，增加了海绵的刚度。在我们的工作中，我们提出了一种替代方法来确保海绵的稳定性，该方法基于化学改性获得的甲基丙烯酸版丝素（Sil-MA）的化学交联。添加光引发剂（LAP）的Sil-MA水溶液允许在紫外线辐射下打开双碳-碳键和自由基聚合。气泡的加入（作为孔隙的模板）是由搅拌器完成的；然后，在紫外线下稳定泡沫，并通过冷冻干燥去除多余的水分。由于光引发剂的细胞毒性（在高浓度使用时发现），在水中引入了额外的洗涤步骤以消除残留物并提高细胞的活力。傅里叶变换红外（FTIR）分析证实了该蛋白的功能化。为了评价各组分对海绵性能的影响，采用了2(3)全因子实验设计。FTIR分析表明，海绵成分对蛋白质的二级结构没有影响。通过分析SEM获得的图像，可以对孔隙度曲线进行一些统计测量并进行建模。同样的建模程序应用于模拟体液中的溶解试验、吸水率和细胞活力（通过MTT和LDH测定）。为每种性质建立了一个经验模型，展示了如何通过改变组成来调整海绵的性质。
Silk fibroin sponges have been widely studied and reported in literature for tissue engineering applications. Several fabrication methods have been proposed during the years to cover most of the demands in terms of properties, which should be adapted to the considered tissue. Most of these procedures are based on the secondary structure transition of the protein to the stable beta crystalline form. This transition, known as physical cross-linking, makes the sponge resistant to dissolution in water, and, in general, increases the sponge stiffness. In our work, we propose an alternative method to ensure the stability of the sponge based on chemical crosslinking of a methacrylated version of silk fibroin (Sil-MA) obtained via chemical modification. The Sil-MA water solution with the addition of a photoinitiator (LAP) allows the opening, under UV radiation, of a double carbon-carbon bond and radical polymerization. The incorporation of air bubbles (that serves as a template for the pores) was accomplished by a mixer; then, the foam was stabilized under UV light and the excess water was removed by freeze-drying. Because of the cytotoxicity of the photoinitiator (found when used at a high concentration), an additional washing step in water has been introduced to eliminate the residues and improve the cells' viability. Fourier transform infrared (FTIR) analysis confirmed the functionalization of the protein. To evaluate the effect of the composition on the sponge properties, a 2(3) full factorial design of the experiment has been adopted. FTIR analysis revealed that the sponge composition did not affect the protein's secondary structure. The analysis of images obtained by SEM allowed some statistical measures of the porosity curves to be studied and modeled. The same modeling procedure was applied to the dissolution test in a simulated body fluid, to the water absorption, and to the cell viability (tested by the MTT and LDH assays). An empirical model for each property was built, showing how by changing the composition it is possible to tune the sponge properties.