(582u) Small Reaction Volume Trend to Produce Monodisperse Gold Nanoparticles in the Biosynthesis By Bacteria

With the development in the field of biotechnology, syntheses of nanoparticles with biomass or biomolecules become more and more popular. In the past several years, many success in the biosyntheses have been reported and various of nanomaterials were produced in this way. Besides the nanomaterials in different morphology, both metal and nonmetal, some achievement in theories are also suggested to give an explaination to the mechanism of the biosynthesis process.

  Compared with syntheses methods, e.g. traditional chemical methods and physical methods, biosyntheses show significant eco-friendly advantage and most biomass or biomolecules only need a mild condition to reduce the metal ions to nanoparticles. According to our knowledge, metal nanoparticles obtained by microbes always show a well monodispersity, which attracts quite a lot attentions. However, some obstruction still restrict the development on a large scale of the biological method, e.g. it is difficult to prepare a large amount of microbes for a commercial process, and separating the nanoparticles from the biomass is also inefficient. As a result, the researchers turn to the imitation of the biological process, and different biomass have been used as reducing agents, in order to find out the key components which play a important role in the morphology control and metal ions reducing. Some amino acids and proteins are reported as the key components and related explainations are also stated,while several experiment are carried on with those, which finally show an unsatisfactory result that only with the key components, the amino acids and proteins, product will have a wider particle size distribution compared with nanoparticles synthesized by microbes.

  What leads to the better monodispersity in microbes？Besides the research focused on the chemical components, we try to get a new explaination which considered the reaction volume as well as the reducing agents. In our experiment, the structure of microbes is ignored because existing knowledge is still weak on the mechanism of the transportation and reducing in the cell of microbes which let it very difficult to prefabricate a man-made microbe. We except to figure out some ideas to improve the monodispersity of existing biological methods, and with a simple analysis to the factor leading to the polydispersity, we finally contribute the polydispersity of the nanoparticles synthesized by simple biomass compared with those synthesized with complex microbes to the unbalance of the reaction rate, diffusion rate and randomness of Nucleation, leading to a relative microcosmic concentration distribution in the close zone of every nucleus or nanoparticles, which make the particle size distribution wider.