School of Biomedical Sciences, Charles Sturt University, Wagga Wagga 2650, Australia.
School of Biomedical Sciences, Charles Sturt University, Wagga Wagga 2650, Australia.
J Mech Behav Biomed Mater. 2019 Feb;90:155-164. doi: 10.1016/j.jmbbm.2018.10.011. Epub 2018 Oct 13.
Sodium alginate is a non-toxic natural polysaccharide found in marine brown algae. It is able to form solid gels by the action of poly-valent cations (commonly calcium but not magnesium) which cross-link the polysaccharide chains at the guluronic acid groups. Alginate-based products are popular in many industries, including food production and in pharmaceutical and biomedical applications. It is utilized in manufacture of wound-care products due to its biocompatibility and gel forming capabilities upon the absorption of wound exudate. Considering the potential influence of the alginate composition on the properties of the resultant fibers, two sodium alginate powders were selected based on their contrasting compositions. The GHB alginate was high in guluronic acid whereas the LKX alginate was high in mannuronic acid. The sodium alginate solutions (4% w/w) were extruded into a calcium chloride (3% w/v) bath to produce calcium alginate fibers. The fibers were dried at 22 °C and 32% relative humidity for 72 h. Selected properties of the blank (unloaded) fibers were analysed: diameter measurements by optical microscopy, mechanical strength using a universal testing machine, morphology by scanning electron microscopy, and calcium content by inductively coupled plasma atomic emission spectroscopy. One of the key aims of this work was to evaluate the variability of these properties along moderately large lengths of fiber and to determine the difference (if any) between replicate lengths of fibers. This study showed that the alginate type influenced selected properties of the resultant fibers. The mean diameter and calcium content of the GHB fibers were 232 µm and 2.79µmoles/mg respectively, whereas the LKX fibers were about 10% thicker and had 2.58µmoles/mg calcium ion content. The fibers of each alginate could be distinguished visually based on gross differences as well as differences in their microstructure. Mechanical testing of the fibers produced stress-strain plots displaying largely non-elastic behaviour. There was no statistically significant (p < 0.05) difference between the Young's modulus or the strain at break for the two types of fibers, namely about 5-5.6 GPa and 0.123-0.131 respectively. All the measured properties were found to be consistent along the nine sampling positions along the lengths of fibers and were reproducible between the different batches of fibers.
海藻酸钠是一种从海洋褐藻中提取的无毒天然多糖。它能够通过多价阳离子（通常是钙离子但不是镁离子）的作用形成固体凝胶，这些多价阳离子在古洛糖醛酸基团处交联多糖链。基于海藻酸盐的产品在许多行业中都很受欢迎，包括食品生产以及制药和生物医学应用。由于其生物相容性以及在吸收伤口渗出物后形成凝胶的能力，它被用于制造伤口护理产品。考虑到海藻酸盐组成对纤维性能的潜在影响，根据其组成的差异，选择了两种海藻酸钠粉末。GHB 海藻酸钠中古洛糖醛酸含量高，而 LKX 海藻酸钠中甘露糖醛酸含量高。将 4%（w/w）的海藻酸钠溶液挤出到 3%（w/v）的氯化钙浴中，以生产出海藻酸钙纤维。纤维在 22°C 和 32%相对湿度下干燥 72 小时。分析了空白（未加载）纤维的一些特性：通过光学显微镜测量直径、使用万能试验机测量机械强度、通过扫描电子显微镜观察形态，以及通过电感耦合等离子体原子发射光谱法测量钙含量。这项工作的一个关键目标是评估这些特性在纤维的中等长度上的可变性，并确定纤维重复长度之间是否存在差异。该研究表明，海藻酸盐类型会影响纤维的一些特性。GHB 纤维的平均直径和钙含量分别为 232µm 和 2.79µmoles/mg，而 LKX 纤维则约厚 10%，钙含量为 2.58µmoles/mg。基于宏观差异以及微观结构的差异，可以很容易地将两种海藻酸盐纤维区分开来。纤维的力学性能测试产生的应力-应变图显示出很大的非弹性行为。两种类型的纤维的杨氏模量或断裂伸长率之间没有统计学上的显著差异（p<0.05），分别约为 5-5.6GPa 和 0.123-0.131。沿着纤维长度的 9 个采样位置测量的所有特性都一致，并且在不同批次的纤维之间具有可重复性。
