高强度丝蛋白/聚乙二醇冻凝胶的制备和表征

以聚乙二醇为交联剂,通过简单的冷冻融化过程制备了一种具有多孔结构的丝蛋白(SF)/聚乙二醇(PEG)高强度冻凝胶材料。利用红外光谱、扫描电镜和万能材料试验机等研究了该冻凝胶的构象转变、微观形貌、力学性能和溶胀行为。结果表明,PEG的加入可以促进SF分子链向更加稳定的结晶构象转变,并且冻凝胶的微观形貌和力学性能通过调节冷冻温度(TFreeze)、PEG用量(mPEG/mSF)和SF质量分数等进行调节。在TFreeze=20℃、wSF=0.16、mPEG/mSF=0.50的条件下,该冻凝胶可以压缩至90%以上,并能承受3.5 MPa应力而不发生永久性形变和破裂,其压缩模量可高达0.44 MPa。循环压缩实验表明该冻凝胶具有出色的回复能力,拉伸测试表明其杨氏模量和韧性可分别达到4.15 MPa和680.81 kJ/m3。此外,该冻凝胶的孔状结构分布均匀、互相连通且溶胀性能优异。

Preparation of High-Strength Silk Fibroin/Polyethylene Glycol Cryogel

A tough,porous silk fibroin(SF)/polyethylene glycol(PEG)cryogel was prepared through a simple freezethawing procedure by using PEG as cross-linking agent.Fourier-transform infrared(FT-IR)spectra,scanning electron microscope(SEM)and universal-testing machine were used to investigate the conformational change,micromorphology,mechanical properties,and swelling behaviors of cryogels.Results demonstrated that the incorporation of PEG faclitated the formation of crystal structures of SF chains,and the microstructure and mechanical properties can be tailored by freezing temperature,mass ratio of PEG to SF(mPEG/mSF),and SF mass fraction.When freezing temperature was−20°C,wSF=0.16,and mPEG/mSF=0.50,the compressive modulus of the SF/PEG cyrogels was up to 0.44 MPa and can tolerant large compressive strain(90%)without permanent deformation and fracture.The cryogel also demonstrated excellent elasticity recovery during cyclic compression test,and the Young’s modulus and toughness of cryogels could reach up to 4.15 MPa and 680.81 kJ/m3,respectively.The cryogels with homogeneously distributed inter-connected porous structure would promote their potential applications in tissue engineering field.