it can be suggested that the antibacterial effects of AgNPs can be associated with types of bacterial species. It is hypothesized that the AgNPs with smaller particles size can easily penetrate to the agar medium and can absorb to the cell surface of bacteria which result in higher antibacterial activity. However, the large AgNPs at ratio lower than 1 did not show the antibacterial properties. The size of nanoparticles ensures that a significantly large surface area of the particles is in contact with the bacterial cell membrane. Considering a spherical particles of uniform size on a theoretical case, a decrease in the particle size from 10 mm to 10 nm will increase the contact surface area by 106 times. Also, inhibition depends on the AgNPs concentrations, which the stabilized AgNPs at lower 6.25 ppm did not prove the bacterial inhibition zones