Rył Anna, Owczarz Piotr
Department of Chemical Engineering, Lodz University of Technology, 90-924 Lodz, Poland.
Polymers (Basel). 2020 Oct 1;12(10):2260. doi: 10.3390/polym12102260.
Low-concentrated colloidal chitosan systems undergoing a thermally induced sol-gel phase transition are willingly studied due to their potential use as minimally invasive injectable scaffolds. Nevertheless, instrumental injectability tests to determine their clinical utility are rarely performed. The aim of this work was to analyze the flow phenomenon of thermosensitive chitosan systems with the addition of disodium β-glycerophosphate through hypodermic needles. Injectability tests were performed using a texture analyzer and hypodermic needles in the sizes 14G-25G. The rheological properties were determined by the flow curve, three-interval thixotropy test (3ITT), and Cox-Merz rule. It was found that reducing the needle diameter and increasing its length and the crosshead speed increased the injection forces. It was claimed that under the considered flow conditions, there was no need to take into account the viscoelastic properties of the medium, and the model used to predict the injection force, based solely on the shear-thinning nature of the experimental material, showed very good agreement with the experimental data in the shear rate range of 200-55,000 s. It was observed that the increase in the shear rate value led to macroscopic structural changes of the chitosan sol caused by the disentangling and ordering of the polysaccharide chains along the shear field.
低浓度胶体壳聚糖体系在热诱导下发生溶胶-凝胶相变，因其有潜力用作微创可注射支架而备受关注。然而，用于确定其临床效用的仪器注射性测试却很少进行。本研究的目的是通过皮下注射针分析添加β-甘油磷酸二钠的热敏壳聚糖体系的流动现象。使用质地分析仪和14G - 25G尺寸的皮下注射针进行注射性测试。通过流动曲线、三区间触变性测试（3ITT）和考克斯-默茨规则测定流变学性质。结果发现，减小针直径、增加针长度和十字头速度会增加注射力。研究表明，在所考虑的流动条件下，无需考虑介质的粘弹性，仅基于实验材料的剪切变稀特性预测注射力的模型，在200 - 55,000 s的剪切速率范围内与实验数据显示出非常好的一致性。观察到剪切速率值的增加导致壳聚糖溶胶的宏观结构变化，这是由多糖链沿剪切场的解缠和排列引起的。
