Department of Chemical Engineering, Aragon Institute of Nanoscience (INA), University of Zaragoza , Campus Rı́o Ebro-Edificio I+D, C/Mariano Esquillor S/N, 50018 Zaragoza, Spain.
Aragon Health Research Institute (IIS Aragón) , 50009 Zaragoza, Spain.
ACS Appl Mater Interfaces. 2017 May 31;9(21):17693-17701. doi: 10.1021/acsami.6b15123. Epub 2017 Mar 3.
The ability of pathogenic bacteria to develop resistance mechanisms to avoid the antimicrobial potential of antibiotics has become an increasing problem for the healthcare system. The search for more effective and selective antimicrobial materials, though not harmful to mammalian cells, seems imperative. Herein we propose the use of gold-chitosan nanocomposites as effective bactericidal materials avoiding damage to human cells. Nanocomposites were obtained by taking advantage of the reductive and stabilizing action of chitosan solutions on two different gold precursor concentrations. The resulting nanocomposites were added at different final concentrations to a coculture model formed by Gram-positive (Staphylococcus aureus) or Gram-negative (Escherichia coli) bacteria and human macrophages. Gold-chitosan colloids exhibited superior bactericidal ability against both bacterial models without showing cytotoxicity on human cells at the concentrations tested. Morphological and in vitro viability studies supported the feasibility of the infection model here described to test novel bactericidal nanomaterials. Flow cytometry and scanning electron microscopy analyses pointed to the disruption of the bacterial wall as the lethal mechanism. Data obtained in the present study suggest that gold-chitosan nanocomposites are powerful and promising nanomaterials for reducing bacteria-associated infections, respecting the integrity of mammalian cells, and displaying high selectivity against the studied bacteria.
致病菌发展出抵抗机制以避免抗生素的抗菌潜力，这对医疗保健系统来说是一个日益严重的问题。寻找更有效和选择性的抗菌材料，虽然对哺乳动物细胞没有危害，但似乎是必要的。在此，我们提出使用金-壳聚糖纳米复合材料作为有效的杀菌材料，避免对人类细胞造成损伤。纳米复合材料是通过利用壳聚糖溶液对两种不同的金前体浓度的还原和稳定作用获得的。将所得纳米复合材料以不同的最终浓度添加到由革兰氏阳性（金黄色葡萄球菌）或革兰氏阴性（大肠杆菌）细菌和人巨噬细胞组成的共培养模型中。金-壳聚糖胶体对两种细菌模型均表现出优异的杀菌能力，在测试浓度下对人细胞没有细胞毒性。形态学和体外生存能力研究支持了在这里描述的感染模型来测试新型杀菌纳米材料的可行性。流式细胞术和扫描电子显微镜分析表明，细菌细胞壁的破坏是致命机制。本研究获得的数据表明，金-壳聚糖纳米复合材料是一种强大且有前途的纳米材料，可用于减少与细菌相关的感染，同时保持哺乳动物细胞的完整性，并对所研究的细菌具有高选择性。
