Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
Mater Sci Eng C Mater Biol Appl. 2017 Apr 1;73:544-551. doi: 10.1016/j.msec.2016.12.066. Epub 2016 Dec 18.
Carboxymethyl chitosan (CMCS) was known to have a much better antimicrobial activity than chitosan due to the increased cationic -NH groups resulted from the intra- and intermolecular interactions between the carboxyl and amino groups. CMCS was grafted onto the surface of silica coated magnetic nanoparticles (MNPs) to obtain magnetically retrievable and deliverable antimicrobial nanoparticles (MNPs@CMCS). The presence of carboxylate groups in CMCS not only enhanced antimicrobial activity but also enabled Ag ions chelating ability to induce the in situ formation of Ag nanoparticles (AgNPs). The deposition of AgNPs on the surface of MNPs@CMCS could significantly increase its antimicrobial activity against planktonic cells due to the dual action of CMCS and AgNPs. Due to its high magnetism, the as-prepared MNPs@CMCS-Ag could be efficiently delivered into an existing biofilm under the guidance of an applied magnetic field. Without direct contact, the Ag ions and/or radical oxygen species (ROS) released from the deposited Ag nanoparticles could effectively kill the bacteria embedded in the extracellular polymeric substances (EPS) matrix of biofilm.
羧甲基壳聚糖（CMCS）由于羧基和氨基之间的分子内和分子间相互作用，增加了阳离子-NH 基团，因此具有比壳聚糖更好的抗菌活性。CMCS 接枝到涂有二氧化硅的磁性纳米颗粒（MNPs）表面上，以获得可回收和可输送的抗菌纳米颗粒（MNPs@CMCS）。CMCS 中存在的羧酸盐基团不仅增强了抗菌活性，而且还使 Ag 离子具有螯合能力，从而诱导 Ag 纳米颗粒（AgNPs）的原位形成。由于 CMCS 和 AgNPs 的双重作用，AgNPs 沉积在 MNPs@CMCS 表面上可显著提高其对浮游细胞的抗菌活性。由于其高磁性，在施加磁场的引导下，所制备的 MNPs@CMCS-Ag 可以有效地递送到现有的生物膜中。Ag 离子和/或从沉积的 Ag 纳米颗粒释放的活性氧（ROS）无需直接接触，即可有效杀死嵌入生物膜细胞外聚合物（EPS）基质中的细菌。
