| Summary: | Silver and copper nanoparticles were produced by chemical reduction of their respective nitrates by
ascorbic acid in the presence of chitosan using microwave heating. Particle size was shown to increase by
increasing the concentration of nitrate and reducing the chitosan concentration. Surface zeta potentials
were positive for all nanoparticles produced and these varied from 27.8 to 33.8 mV.Antibacterial activities
of Ag, Cu, mixtures of Ag and Cu, and Ag/Cu bimetallic nanoparticles were tested using Bacillus subtilis and
Escherichia coli. Of the two, B. subtilis proved more susceptible under all conditions investigated. Silver
nanoparticles displayed higher activity than copper nanoparticles and mixtures of nanoparticles of the
same mean particle size. However when compared on an equal concentration basis Cu nanoparticles
proved more lethal to the bacteria due to a higher surface area. The highest antibacterial activity was
obtained with bimetallic Ag/Cu nanoparticles with minimum inhibitory concentrations (MIC) of 0.054
and 0.076 mg/L against B. subtilis and E. coli, respectively.
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