Nisbet D R, Crompton K E, Hamilton S D, Shirakawa S, Prankerd R J, Finkelstein D I, Horne M K, Forsythe J S
Department of Materials Engineering, Monash University, Wellington Rd, Clayton, VIC 3800, Australia.
Biophys Chem. 2006 Apr 20;121(1):14-20. doi: 10.1016/j.bpc.2005.12.005. Epub 2006 Jan 9.
Galactose modified xyloglucan is a thermally reversible hydrogel that is increasingly used in the biomedical field due to the ease of altering the gelation time and temperature by modifying the galactose removal ratio. However there is little information concerning the morphology and rheological properties of the hydrogel under physiological conditions. Differential scanning microcalorimetry (DSmicroC) showed the thermal gelation process to occur over a broad temperature range (5-50 degrees C). The rheological properties of the hydrogels were investigated as a function of concentration, temperature and ionic strength. The final elastic moduli of the hydrogels increased with increases in concentration. Isothermal rheology suggests that the gelation occurred in two distinct stages, which was influenced by the solution media. Scanning electron microscopy (SEM) was used to characterize the morphology of the xyloglucan which were thermally gelled at 37 degrees C. The resultant morphology was strongly dependent on the concentration of the hydrogel. Strong hydrogels were only obtained at 3 wt.% at 37 degrees C, and the morphology characterized by an open 3-dimensional network, comprised of thin membranes. It is proposed that the first stage of the isothermal gelation is the formation and growth of the thin membranes, followed by the formation of a three dimensional network.
半乳糖修饰的木葡聚糖是一种热可逆水凝胶，由于通过改变半乳糖去除率可以轻松改变凝胶化时间和温度，因此在生物医学领域的应用越来越广泛。然而，关于该水凝胶在生理条件下的形态和流变学性质的信息却很少。差示扫描量热法（DSmicroC）显示热凝胶化过程在较宽的温度范围（5-50摄氏度）内发生。研究了水凝胶的流变学性质随浓度、温度和离子强度的变化。水凝胶的最终弹性模量随浓度的增加而增加。等温流变学表明凝胶化过程分两个不同阶段发生，这受溶液介质的影响。扫描电子显微镜（SEM）用于表征在37摄氏度下热凝胶化的木葡聚糖的形态。所得形态强烈依赖于水凝胶的浓度。仅在37摄氏度下3 wt.%的浓度时才能得到强水凝胶，其形态特征为开放的三维网络，由薄膜组成。有人提出等温凝胶化的第一阶段是薄膜的形成和生长，随后是三维网络的形成。
