Li Shue, Mu Bin, Zhang Hong, Kang Yuru, Wang Aiqin
Key Laboratory of Clay Mineral Applied Research of Gansu Province, Center of Eco-Material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China.
Key Laboratory of Clay Mineral Applied Research of Gansu Province, Center of Eco-Material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
Int J Biol Macromol. 2022 Dec 31;223(Pt A):779-789. doi: 10.1016/j.ijbiomac.2022.11.046. Epub 2022 Nov 10.
It is popular that natural organics are served as green reducing and end-capping reagent for synthesis of functional nanoparticles. In this study, curcumin, a natural pigment, was employed to prepare silver nanoparticles (AgNPs) as a coloring, reducing and end-capping agent by an eco-friendly, economic and facile approach in the presence of different clay minerals, including palygorskite, montmorillonite and mixed-dimensional palygorskite clay. It was found that the phenolic hydroxyl groups or carbonyl groups of curcumin played a crucial role to reduce silver ions into AgNPs with the ginger color. Meanwhile, incorporation of clay minerals could induce the in-situ heterogeneous nucleation of AgNPs on the surface or/and interlayer of the involved clay minerals. It effectively prevented from the aggregations and resulted in uniform dispersion of AgNPs with a diameter of 30-40 nm. Furthermore, the as-prepared nanocomposites exhibited a higher antioxidant (>90%) and antibacterial activity. Due to the synergistic effect of each component among the nanocompositions, the nanocomposites derived from different clay minerals were employed as multifunctional nanofillers to design functional chitosan composite films. By contrast, the chitosan composite films containing curcumin-capped AgNPs/mixed-dimensional palygorskite clay nanocomposites exhibited the best mechanical properties, antioxidant and antibacterial activities. Compared with the chitosan films, the tensile strength and elongation at break of composite films increased by 15.90 MPa and 27.27%, respectively. The inactivation rate of the composite films against Escherichia coli and Staphylococcus aureus had reached 100%. Therefore, the obtained composite film with the ginger color exhibited excellent mechanical, water resistance, antioxidant and antibacterial properties, and it was expected to develop a great potential functional packaging materials.
天然有机物作为绿色还原剂和封端剂用于合成功能纳米粒子已很普遍。在本研究中，天然色素姜黄素被用于通过一种环保、经济且简便的方法，在包括坡缕石、蒙脱石和混合维坡缕石粘土等不同粘土矿物存在的情况下，制备银纳米粒子（AgNPs），作为着色剂、还原剂和封端剂。研究发现，姜黄素的酚羟基或羰基在将银离子还原为具有姜黄色的AgNPs过程中起关键作用。同时，粘土矿物的加入可诱导AgNPs在相关粘土矿物的表面或/和层间原位异质成核。这有效地防止了团聚，导致直径为30 - 40nm的AgNPs均匀分散。此外，所制备的纳米复合材料表现出较高的抗氧化活性（>90%）和抗菌活性。由于纳米复合材料中各组分的协同作用，源自不同粘土矿物的纳米复合材料被用作多功能纳米填料来设计功能性壳聚糖复合膜。相比之下，含有姜黄素封端的AgNPs/混合维坡缕石粘土纳米复合材料的壳聚糖复合膜表现出最佳的机械性能、抗氧化和抗菌活性。与壳聚糖膜相比，复合膜的拉伸强度和断裂伸长率分别提高了15.90MPa和27.27%。复合膜对大肠杆菌和金黄色葡萄球菌的灭活率达到了100%。因此，所获得的具有姜黄色的复合膜表现出优异的机械、耐水性、抗氧化和抗菌性能，有望开发出具有巨大潜力的功能性包装材料。
