Controllable Synthesis Of Metal Nanoparticles In The Artificial Quasi-Biological System

In past decades, the development of nanotechnology has brought a profound revolution in the cognition of human beings. As an interdisciplinary subject, the research of nanotechnology involves many fields of modern science and technology. The preparation and performance study of nanomaterials based on physics and chemistry are the foundation of the whole nanotechnology. Metal nanoparticles are the most studied nanomaterials which have been investigated for more than one hundred years. Due to their unique physical and chemical properties, metal nanoparticles have been widely used in bio-assay, medical diagnosis, fabrication of electronic devices, catalysis and so on. At present, metal nanoparticles are mostly obtained by so-called "bottom-up" method, relying on the chemical reduction of metal salts in solution. Generally, these methods need strong reducing agents or are energy-efficient, requiring high-temperature or high-pressure. In accordance with the requirement of green chemistry and sustainable development, it is of great importance to develop new methods of preparing metal nanoparticles.The research of microbes has inspired researchers to utilize diverse biomolecules and efficient biochemical reactions in nanotechnology. Biological and biomimetic methods have provided new routes as supplements for preparation of nanomaterials. But the difficulty of controlling the size and distribution of products is an urgent problem existing in the biological or biomimetic syntheses of nanomaterialsIn previous work, through a novel biological strategy of coupling intracellular irrelated biochemical reactions, uniform fluorescent CdSe quantum dots with color controllability of photoluminescence could be synthesized in living yeast cells under mild conditions. In the dissertation, we simulate the cellular conditions and create a quasi-biological system containing electrolytes, peptide, enzyme and coenzyme inspired from our biosynthesis using living cells. Based on the quasi-biological system, we have done the following work:(1) Monodisperse water-soluble AuNPs with tunable sizes have been successfully synthesized under mild conditions in the quasi-biological system; the mechanism has been proposed based on the characterization of intermediate; the crystallization process have been discussed; meanwhile, the biomimetic characteristics and influence factors of the reaction have been systematically analyzed. (2) By rationally utilizing the properties of the reduction and kinetically controlling the reduction process in the quasi-biological system, water-soluble glutathione-capped Au clusters with have been successfully synthesized. The structure and properties have been characterized.(3) Based on the structure and properties of reducing agent used in the synthesis in the quasi-biological system, we have developed new methods for the preparation of small-sized Ag nanoparticles and Au-Ag alloy nanoparticles.This strategy of creating a quasi-biological system for the controllable preparation of nanomaterials under mild conditions may provide an important complement of conventional chemical syntheses and open a new way for the sustainable development of nanotechnology.