Chemical generation of high stability silver nanoparticles for biological research.

摘要

Research and development of silver nanoparticle technology are currently among the fastest growing areas in the nanosciences due to the wide range of applications from photographic films to bactericides. For most of these technological applications, physically and chemically stabilized silver nanoparticles are required. Also, the control of the composition and properties of the nanoparticles is of utmost importance. Current stabilization methods mostly utilize polymeric and organic phase based surfactants to prevent agglomeration of nanoparticles. However, these additives preclude the use of the nanoparticles for biological research and applications due to toxicity. One of the main goals of this thesis research is the formulation of silver nanoparticle systems which are not limited by the toxicity of their stabilizing agents, but are configured for use in micro biological research.;The development and optimization of chemical procedures to generate chemically and physically stable silver nanoparticle media were of central importance to this thesis project. Therefore a large number of chemical systems were investigated as a function of numerous variables. First, investigations of various chemical reactions were explored to optimize the properties of the resulting nanoparticles. Then, a suitably optimized chemical method was scaled for easily producing a large-volume synthesis of the material. Scaled production was accomplished by developing an ac potential electrochemical process which was optimized as the best method for generating pristine nano-materials suitable for use in nano-biomolecular research. The advantages of the electrochemical method for synthesis of nanoparticles are contrasted with those of the chemical reduction method. The electrochemical synthesis was shown to be a more optimum process due to the minimal introduction of contaminants and chemical by-products, and low levels of excess silver cations. Reactions driven by induced electron flow as opposed to the introduction of various chemical reductants minimized the yield of potential by-products and excess starting reagents.;In summary, the accomplishments in this thesis include the generation of chemically and physically stabilized pure silver citrate nanoparticles. Also, an optimized small-scale electrochemical process was successfully scaled-up utilizing a custom designed preparatory-scale electrochemical apparatus. The media generated in both the small-scale and laboratory-scale systems were used to produce nanoparticle doped in vitro biological experiments, meeting all the criteria of purity through chemical and physical stability. This is believed to be unprecedented in current literature. This thesis validates that the electrochemical synthesis described in this research produces silver nanoparticle media that is viable for research in the biological arena.