Results of studies on antibacterial properties of silver nanoparticles proposed
that silver nanoparticles may attach to the cell membrane surface, which causes change in cell permeability and finally cell death (Rai et al. 2009). Moreover,there is a possibility of their penetration into the bacteria,resulting in cell death. Thus, the smaller silver nanoparticles have the larger available surface area for binding to the cell membrane surface of bacteria.