ANTI-MICROBIAL ACTIVITY OF SILVER-IMPREGNATED ALUMINA IN A HARD WATER ENVIRONMENT(Abstract)

摘要

Nano-sized silver particles have numerous commercial applications, including disinfection of water, food processing and disinfection of healthcare equipment. It has been shown that silver interacts with the cell membranes of bacteria, which alters their mesosomal functions, such as their ability to aid DNA replication. As an anti-microbial agent, silver quickly binds to the sulphydryl groups of oxygen utilizing enzymes which ultimately leads to oxygen deprivation and bacterial cell destruction. In Escherichia coli, which are also vulnerable to silver, it has been suggested that the lipopolysaccharides on their surface contain high affinity binding sites for divalent cations. The aim of this study is to understand the nature of the bactericidal activity of silver impregnated alumina, its mechanistic details, and properties that influence disinfection. Specifically, we are investigating the anti-microbial properties of silver impregnated alumina in a hard water environment, with hopes of determining how this media functions as an antimicrobial agent. We hypothesize that the silver that is in complex with the alumina surface destroys bacteria by oxidation of the plasma membrane and inhibition of its energy metabolism. To study this hypothesis, we exposed E. coli to metallic silver impregnated on the surface of alumina and determined its effects in compromising cellular integrity and disrupting cellular processes. In addition, the effect of hard water on the ability of silver impregnated alumina to kill bacteria was also examined. The results of this study reveal that silver’s ability to kill bacteria is dose dependent, and the effect of hard water silver impregnated alumina on cellular integrity is inconclusive. This study will lead to a better understanding of silver impregnated alumina’s mechanism of anti-microbial effect, thereby aiding in the design and synthesis of improved anti-microbial materials for water purification and storage. This project supported by NSF Grant # CTS-0120978, Water CAMPWS, and NIH Grant #GM08247.