Synthetic bone void fillers based on calcium ceramics are used to fill cavities in the bone and promote bone regeneration. More recently, silk fibroin (SF), a protein polymer obtained from Bombyx mori silkworm, has emerged as a promising material in bone void filling. In this work, we have compared the safety and efficacy of two types of silk fibroin-based bone void fillers with currently used and commercially available ceramic bone void fillers (based on calcium sulphate, beta tricalcium phosphate, and beta tricalcium phosphate with hydroxyapatite). Further, we have also evaluated these two types of SF scaffolds, which have strikingly different structural attributes. The biocompatibility of these scaffolds was comparable as assessed by cytotoxicity assay, cellular adhesion assay, and immunogenic assay. Ability of the scaffolds to support differentiation of human mesenchymal stem cells (hMSCs) into an osteoblastic lineage was also evaluated in an in vitro differentiation experiment using reverse transcriptase polymerase chain reaction analysis. These results revealed that cells cultured on SF scaffolds exhibit higher expression of early to late markers such as Runx2, BMPs, collagen, osterix, osteopontin, and osteocalcin as compared with ceramic-based scaffolds. This observation was further validated by studying the expression of alkaline phosphatase and calcium deposition. We also show that scaffolds made from same material of SF, but characterized by very different pore architectures, have diverse outcome in stem cell differentiation.

中文翻译：

---

丝素蛋白和陶瓷支架：骨再生的体外比较研究

基于钙陶瓷的合成骨空隙填充物用于填充骨中的空腔并促进骨再生。最近，丝素蛋白 (SF)，一种从家蚕中获得的蛋白质聚合物蚕，已成为骨空隙填充的有前途的材料。在这项工作中，我们比较了两种基于丝素蛋白的骨空隙填充剂与目前使用和市售的陶瓷骨空隙填充剂（基于硫酸钙、β 磷酸三钙和β 磷酸三钙与羟基磷灰石）的安全性和有效性。此外，我们还评估了这两种类型的 SF 支架，它们具有显着不同的结构属性。这些支架的生物相容性通过细胞毒性测定、细胞粘附测定和免疫原性测定进行评估。在使用逆转录酶聚合酶链反应分析的体外分化实验中，还评估了支架支持人间充质干细胞 (hMSC) 分化为成骨细胞谱系的能力。这些结果表明，与基于陶瓷的支架相比，在 SF 支架上培养的细胞表现出更高的早期至晚期标志物表达，例如 Runx2、BMP、胶原蛋白、osterix、骨桥蛋白和骨钙素。通过研究碱性磷酸酶和钙沉积的表达进一步验证了这一观察结果。我们还表明，由相同的 SF 材料制成的支架，但具有非常不同的孔结构，在干细胞分化中具有不同的结果。