Wen Yan, Tan Zhilei, Sun Fang, Sheng Li, Zhang Xiaoyang, Yao Fanglian
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; School of Science, Tianjin University of Commerce, Tianjin 300134, China.
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300222, China.
Mater Sci Eng C Mater Biol Appl. 2012 Oct 1;32(7):2026-2036. doi: 10.1016/j.msec.2012.05.019. Epub 2012 May 27.
With the aim to develop a novel water-soluble modified chitosan nanoparticle with tuned size and improved antibacterial activity, quaternized carboxymethyl chitosan/poly(amidoamine) dendrimers (CM-HTCC/PAMAM) were synthesized. Firstly low-generation amino-terminated poly(amidoamine) (PAMAM) dendrimers were prepared via repetitive reactions between Michael addition and amidation, which were then employed for modifying quaternized carboxymethyl chitosan (CM-HTCC). Prior to the reaction of CM-HTCC with PAMAM, carboxylic groups in CM-HTCC were activated with EDC/NHS in order to enhance the reaction efficiency. FT-IR, H NMR, elemental analysis and XRD were performed to characterize CM-HTCC/PAMAM dendrimers. Turbidity measurements showed that CM-HTCC/PAMAM dendrimers had good water-solubility. TEM images indicated that CM-HTCC/PAMAM dendrimers existed as smooth and spherical nanoparticles in aqueous solution. The results of antibacterial activity explored that CM-HTCC/PAMAM dendrimer nanoparticles displayed higher antibacterial activity against Gram-negative bacteria Escherichia coli (E. coli), whereas they showed much less efficiency against Gram-positive bacteria Staphylococcus aureus (S. aureus) compared to quaternized chitosan (HTCC).
为了开发一种具有可调尺寸和增强抗菌活性的新型水溶性改性壳聚糖纳米颗粒，合成了季铵化羧甲基壳聚糖/聚（酰胺胺）树枝状大分子（CM-HTCC/PAMAM）。首先，通过迈克尔加成和酰胺化之间的重复反应制备低代氨基封端的聚（酰胺胺）（PAMAM）树枝状大分子，然后将其用于修饰季铵化羧甲基壳聚糖（CM-HTCC）。在CM-HTCC与PAMAM反应之前，用EDC/NHS活化CM-HTCC中的羧基以提高反应效率。进行了傅里叶变换红外光谱（FT-IR）、核磁共振氢谱（1H NMR）、元素分析和X射线衍射（XRD）来表征CM-HTCC/PAMAM树枝状大分子。浊度测量表明CM-HTCC/PAMAM树枝状大分子具有良好的水溶性。透射电子显微镜（TEM）图像表明CM-HTCC/PAMAM树枝状大分子在水溶液中以光滑的球形纳米颗粒形式存在。抗菌活性结果表明，与季铵化壳聚糖（HTCC）相比，CM-HTCC/PAMAM树枝状大分子纳米颗粒对革兰氏阴性菌大肠杆菌（E. coli）表现出更高的抗菌活性，而对革兰氏阳性菌金黄色葡萄球菌（S. aureus）的抗菌效率则低得多。
