The occurrence of colour was indicated the
formation of silver nanoparticles. The silver nanoparticles
were purified by centrifugation. To remove excess silver ions,
the silver colloids were washed at least three times with
deionized water under nitrogen stream. A dried powder of the
nanosize silver was obtained by freeze-drying. To carry out all
characterization methods and interaction of the silver
nanoparticles with bacteria, the silver nanoparticle powder in
the freeze-drying cuvette was resuspended in deionized water;
the suspension was homogenized with a Fisher Bioblock
Scientific ultrasonic cleaning container.