材料期刊网

以碱基对数为7.5 kB的大肠杆菌环状质粒DNA为模板, 通过紫外线辐射作用下的光化学反应方法制备了Ag纳米颗粒. 采用紫外--可见光吸收光谱, TEM和EDS等方法研究了辐射时间、溶液浓度等工艺条件对Ag纳米颗粒组成、形貌和结构的影响. 结果表明, 获得的Ag纳米颗粒为fcc结构, 颗粒直径为25-40 nm; 一定条件下, Ag纳米颗粒为环状, 中间孔洞直径为8-10 nm, Ag⁺与碱基对数摩尔比为4、辐射时间为40 min时, Ag纳米颗粒中环状结构最多.

Over the past two decades, interest has been focused on the synthesis of novel nanomaterials with different sizes and different morphologies due to their intriguing chemical, electronic, biosensing, optical and catalytic properties. The biomacromolecules like nucleic acids, proteins, amino acids and peptides have been employed as template for nanomaterial design and synthesis. DNA, which could self-assemble into complex structures such as cubes and squares, is being actively explored for the synthesis of nanomaterials with novel structures and unexpected properties. In this work, the plasmid DNA with 7.5 kB base pairs separated from the bacillus was used as a template to prepare Ag nanoparticles based on the ultraviolet ray (UV) photoirradiation method. The effects of experimental conditions, such as the photoirradiation time and concentration of metallic Ag⁺ ions, on the composition, morphology, and structure of the obtained nanoparticles were detailed studied. The Ag nanoparticles were characterized by using UV--visible light absorption spectroscopy, TEM and EDS. It is found that Ag⁺ and UV are necessary in this preparation based on plasmid DNA. The resulted Ag nanoparticles are fcc structure, and the average diameter of obtained nanoparticles is 25-40 nm. The sizes of nanoparticles increased with the increasing of the photoirradiation time and the concentration of Ag⁺. When the mol ratio of Ag⁺ to base pairs is 4∶1 and the photoirradiation time is 40 min, the obtained nanoparticles are almost ring-shape with inner diameter of 8-10 nm. In synthesizing process of Ag nanoparticles, only plasmid DNA and Ag⁺ ions solution were needed, and the plasmid DNA worked not only as template to drive the formation of the Ag nanoparticles, but also as reducer to reduce the Ag⁺ ions to be metallic Ag. This synthesis method could also be used to prepare other metallic or semiconducting nanoparticles.