仿生各向异性结构复合水凝胶及其流变学行为

Rheological Behavior of Biomimetic Composite Hydrogels with Anisotropic Structures

仿生构筑具有动态黏弹性行为的细胞外微环境,是组织工程领域细胞外基质(ECM)设计的重要策略.本研究通过定向冷冻和限域拉伸干燥再溶胀的协同策略构建了具有各向异性结构的聚乙烯醇(PVA)/纤维素纳米纤维(CNF)复合水凝胶.所制备的复合水凝胶呈现出平行于定向冷冻方向的取向纤维排列结构.流变学实验结果表明,PVA/CNF复合水凝胶具有各向异性的动态模量(G′_(∥)=(76.77±1.61)kPa和G′_(⊥)=(42.93±1.34)kPa;G″_(∥)=(5.44±0.26)kPa和G″_(⊥)=(3.71±0.13)kPa),其储能模量(G′)和损耗模量(G″)在低频率和低应变区域随PVA含量的增加而增大,随CNF含量的增加呈现先增大后减小的变化趋势.应力松弛实验结果表明,复合水凝胶基质具有黏弹性特性.本文所总结的具有各向异性结构复合水凝胶的黏弹性性质及其规律,对于指导组织工程仿生ECM的设计及其对细胞生物行为的影响方面具有潜在的应用价值.

Biomimetic construction of extracellular microenvironment with dynamic viscoelastic behavior is an important strategy for the design of extracellular matrix(ECM)in tissue engineering.In this study,a poly(vinyl alcohol)(PVA)/cellulose nanofiber(CNF)composite hydrogel with anisotropic structure was constructed through the cooperative strategy of directional freezing(DF)and confined drying and re-swelling(CDR).The prepared composite hydrogel showed the oriented fiber arrangement structure parallel to the directional freezing direction.Rheological experiments showed that PVA/CNF composite hydrogel had anisotropic dynamic modulus(G′_(∥)=(76.77±1.61)kPa and G′_(⊥)=(42.93±1.34)kPa;G″_(∥)=(5.44±0.26)kPa and G″_(⊥)=(3.71±0.13)kPa).The energy storage modulus(G′)and loss modulus(G″)improved with the increase of PVA content in the low frequency and low strain regions,and showed a tendency of increasing and then decreasing with the increase of CNF content.The results of stress relaxation experiments indicated that the composite hydrogel had viscoelastic properties.Therefore,the viscoelastic properties and rules of the composite hydrogel with anisotropic structures summarized in this study have potential applications in guiding the design of tissue-engineered biomimetic ECM and its effect on cell biological behavior.