Silver nanoparticles are typically used in the size range of 1-50nm. At this very small size, the particles’ surface area is large comparative to its volume. The comparatively large surface area of nanoparticles increases their reactivity, which in many instances also increases toxicity. For instance, Elechiguerra et al showed that interaction with the HIV-I virus is highly size dependent, with silver nanoparticles in the 1-10nm range exclusively attaching to the virus and consequently inhibiting it from binding to hosts cells.