Department of Food Science, Fu Jen Catholic University, New Taipei City 242, Taiwan.
Department of Food Science, Fu Jen Catholic University, New Taipei City 242, Taiwan.
Int J Biol Macromol. 2020 Oct 15;161:1484-1495. doi: 10.1016/j.ijbiomac.2020.07.244. Epub 2020 Aug 7.
Gold nanoparticles capped with chitosan (CH-NGs), glycol chitosan (GC-NGs) and poly(γ-glutamic acid) (PA-NGs) were synthesized separately, characterized and evaluated for catalytic and antibacterial activities. Surface Plasmon resonance peak at 520-530 nm confirmed the formation of NGs, while FTIR spectra revealed the involvement of hydroxyl, amine and amide groups in biopolymers on NGs formation and coating. Particle size, zeta potential and surface coating were respectively 21.7 nm, +50.2 mV and 20% for CH-NGs, 5.6 nm, +46.5 mV and 43.5% for GC-NGs and 7.4 nm, -37.3 mV and 34.5% for PA-NGs. Compared to citrate-capped NGs (CT-NGs), biopolymer-capped NGs exhibited high catalytic activity in a 4-nitrophenol reduction model with the pseudo first-order catalytic rate for PA-NGs being 4-6 fold higher than CH-NGs and GC-NGs. No significant antibacterial effect was shown for CT-NGs. However, PA-NGs was superior to gentamycin in inhibiting Salmonella enterica and Escherichia coli-O157:H7, while CH-NGs and GC-NGs showed the highest antibacterial effect against Listeria monocytogenes, followed by Salmonella enterica, Escherichia coli-O157:H7, methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus. TEM images showed that GC-NGs were attached on MRSA surface to alter cell permeability, block nutrient flow and disrupt cell membrane, whereas PA-NGs penetrated into Salmonella enterica to generate cavities, plasmolysis and disintegration.
分别合成了壳聚糖（CH-NGs）、乙二醇壳聚糖（GC-NGs）和聚（γ-谷氨酸）（PA-NGs）包覆的金纳米颗粒，并对其进行了表征和催化活性及抗菌活性评价。520-530nm 的表面等离子体共振峰证实了 NGs 的形成，而傅里叶变换红外光谱（FTIR）则表明羟基、胺基和酰胺基参与了生物聚合物在 NGs 形成和包覆过程。CH-NGs 的粒径、zeta 电位和表面包覆率分别为 21.7nm、+50.2mV 和 20%，GC-NGs 为 5.6nm、+46.5mV 和 43.5%，PA-NGs 为 7.4nm、-37.3mV 和 34.5%。与柠檬酸包覆的 NGs（CT-NGs）相比，生物聚合物包覆的 NGs 在 4-硝基苯酚还原模型中表现出较高的催化活性，其中 PA-NGs 的拟一级催化速率比 CH-NGs 和 GC-NGs 高 4-6 倍。CT-NGs 没有表现出明显的抗菌效果。然而，PA-NGs 在抑制肠炎沙门氏菌和大肠杆菌 O157:H7 方面优于庆大霉素，而 CH-NGs 和 GC-NGs 对单核细胞增生李斯特菌表现出最高的抗菌效果，其次是肠炎沙门氏菌、大肠杆菌 O157:H7、耐甲氧西林金黄色葡萄球菌（MRSA）和金黄色葡萄球菌。透射电子显微镜（TEM）图像显示，GC-NGs 附着在 MRSA 表面，改变细胞通透性，阻断营养物质流动并破坏细胞膜，而 PA-NGs 则穿透肠炎沙门氏菌，产生空泡、质壁分离和崩解。
