Department of Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Colloids Surf B Biointerfaces. 2010 Jun 1;77(2):219-26. doi: 10.1016/j.colsurfb.2010.01.029. Epub 2010 Feb 4.
The core-shell nanoparticles possessing poly(methyl methacrylate) (PMMA) core coated with chitosan (CS), polyethyleneimine (PEI), and chitosan-mixed-polyethyleneimine (CS/PEI) shells were synthesized in this work. The emulsifier-free emulsion polymerization triggered by a redox initiating system from t-butylhydroperoxide (TBHP) and amine groups on CS and/or PEI was used as a synthetic method. In the CS/PEI systems, the amount of CS was kept constant (0.5g), while the amount of PEI was varied from 0.1 to 0.5g. The surface and physico-chemical properties of prepared nanoparticles were then examined. FTIR spectra indicated the presence of grafted PMMA on CS and/or PEI, and the weight fraction of incorporated PEI in the CS/PEI nanoparticles. All nanoparticles were spherical in shape with uniform size distribution illustrated by scanning electron microscopy (SEM). The introduction of PEI to CS nanoparticles yielded the higher monomer conversion, grafting efficiency, and grafting percentage compared with the CS nanoparticles. The size of CS/PEI nanoparticles was smaller than the original CS and PEI nanoparticles, and tended to decrease with increasing amount of PEI introduced. The introduction of PEI also brought the higher colloidal stability to the nanoparticles as indicated by zeta-potential measurement and isoelectric point analysis. The nanoparticles exhibited a promising antibacterial activity against Staphylococcus aureus and Escherichia coli. The nanoparticle-bacteria interaction was studied via SEM. The results suggested that they would be useful as effective antibacterial agents.
本工作合成了具有聚甲基丙烯酸甲酯（PMMA）核壳纳米粒子，其壳层分别由壳聚糖（CS）、聚乙烯亚胺（PEI）和 CS/PEI 组成。采用由叔丁基过氧化氢（TBHP）和 CS 及/或 PEI 上的伯胺引发的氧化还原引发体系引发无乳化剂乳液聚合作为合成方法。在 CS/PEI 体系中，CS 的量保持不变（0.5g），而 PEI 的量从 0.1 至 0.5g 变化。然后检查了制备的纳米粒子的表面和物理化学性质。傅里叶变换红外光谱（FTIR）表明存在接枝到 CS 和/或 PEI 上的 PMMA，以及 CS/PEI 纳米粒子中结合的 PEI 的重量分数。所有纳米粒子均为球形，具有均匀的尺寸分布，通过扫描电子显微镜（SEM）显示。与 CS 纳米粒子相比，PEI 的引入导致更高的单体转化率、接枝效率和接枝百分比。CS/PEI 纳米粒子的尺寸小于原始 CS 和 PEI 纳米粒子，并且随着引入的 PEI 量的增加而趋于减小。PEI 的引入还使纳米粒子具有更高的胶体稳定性，如通过动电位测量和等电点分析所表明的那样。纳米粒子对金黄色葡萄球菌和大肠杆菌表现出有希望的抗菌活性。通过 SEM 研究了纳米粒子-细菌相互作用。结果表明，它们将作为有效的抗菌剂很有用。
