丝素蛋白支架在骨组织工程中的应用进展

Synthesis and application progression of silk fibroin scaffold in bone tissue engineering

支架材料作为骨组织工程的核心部分，其生物结构、功能和制备方法弓l起众多关注。理想的支架材料需具备足够的力学强度、适当的降解速度、良好的生物相容性、容易获得、价格低廉等优点。常见的支架材料主要包括无机物、有机物及天然衍生物。作为新型的支架，丝素蛋白支架的主要结构是从蚕丝中提取的天然高分子纤维蛋白，含有18种氨基酸，以甘氨酸、丙氨酸和丝氨酸为主，其结构由复杂的氢键、疏水键和结晶区组成，具有良好的柔韧性和抗拉伸强度，以及较好的透气、透湿性和生物降解功能。此外，其固化结晶方式的多样化，易于保持高度生物亲和性以及形成特殊的多孔性结构。丝素蛋白还具有优良的成膜和成凝胶特性，并且通过与其他天然高分子材料的复合与化学改性，可进一步改善其理化性质。丝素蛋白可制备成多孔支架、纤维膜支架、凝胶支架以及复合材料支架，这些支架材料具有力学性能优异、降解速度可调、生物相容性高、成骨性能良好等特点，此外还能负载细胞、生物活性因子以及药物。可通过不同的处理方法或复合其他材料，制备成丝素凝胶支架（将丝素蛋白内的氨基酸序列由无序结构转变为13折叠结构，从而形成理化性质稳定的凝胶）、丝素多孔支架（通过盐析、发泡、冻干等方法制备）、丝素电纺纤维支架（通过电纺制备）及丝素复合支架（主要通过盐析制备）等具有三维多孔和生物学功能的新型材料，为骨组织工程提供新的选择和应用前景。

The essentiai factors of bone tissue engineering include seedcell, growth factor and scaffold material. The bio- logical structure, biological function and preparation method of scaffold material, which is the key component in bone tissue engi- neering, have attracted our attention. An ideal scaffold material needs to have adequate mechanical strength, appropriate degrada- tion speed, good biocompatibility, satisfactory availability, low price, et al. Common scaffold materials in bone tissue engineering mainly consist of inorganic matter, organic matter and natural derivatives. Silk fibroin which is extracted from silkworm protein fi- ber contains 18 kinds of amino acids. The glycine, alanine, serine are the main types in silk fibroin and its structure consisted of hydrogen bonding, hydrophobic bonding and crystalline region. Those special structures make it has good flexibility and tensile strength. Silk fibroin has other advantages incluing air permeability, moisture permeability and biodegradation. Besides silk fibro- in with curing crystallization of diversification that easy to maintain biological affinity and form a special porous structure. Silk fi- broin has good film and gel forming ability. Silk fibroin can bond with some other materials to further improve its physical and chemical properties. Silk fibroin can be formed into porous shape, membranous, gel and composite materials scaffold. The materi- als scaffold which based on silk fibroin has excellent mechanical performance, adjustable degradation speed, high biocompatibility and good osteogenesis performance, besides capability of loading cells, bioactive factors and drugs. In addition, silk fibroin which can be made into gel scaffold,porous scaffold,electrospinning fiber,and compound scaffold et al has three-dimensional porous and biological function for bone tissue engineering as a new choice and application prospect.