Silver Armor Against Bacteria: A Battle of Antimicrobial Effectiveness

Overview

For many farmers, finding efficient ways to fight infection strengthens their business and saves their crops. Florida's climate makes agriculture especially susceptible to disease or the elements. Thus, I set out to explore if a traditional at-home remedy, colloidal silver, could be used as an effective inhibitor of bacterial growth, comparing effects across gram-negative and gram-positive species. I started by creating my colloidal silver, suspending silver particles in a solvent. Wiring eight nine-volt batteries, I created my colloidal silver machine. It ran an electrical current through suspended silver jewelry chains in a container of distilled water to create colloidal silver treatments. I compared these treatments to a storebought solution via the Kirby-Baur method. Petri dishes were divided into four quadrants, and a treatment-soaked square was placed in each. So, every plate had four square paper blots in them, each with differing silver. After taping the plates closed, I recorded the dimensions of Zones of Clearance (ZOC) and unexpected bacterial growth surrounding treatment squares. The experiment was replicated four times. I analyzed using one-way ANOVA with post hoc separation of means using the T-test and Tukey's HSD. The positive control solution was the most effective bactericide across all species, followed by Treatment-2, which caused ZOC in gram-negative species. The homemade 3ppm did not significantly affect bacterial suppression, while activity at 5ppm suggests that colloidal systems could produce antibacterial solutions. It was noted that a beneficial plant bacterium showed an increase in growth after Treatment-3. Improving homemade systems may provide a low-cost treatment solution against some bacteria species important to backyard agriculturists.

Competition history

• ISEF 2024 Plant Sciences · Entry PLNT007 · Los Angeles, California, United States

Resources

• ISEF abstract page ↗

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