Safety issues

Nanoparticles present possible dangers, both medically and environmentally.

[20]

Most of these are due to the high surface to volume ratio, which can make the particles very reactive or

catalytic

.

[21]

They are also able to pass through

cell membranes

in organisms, and their interactions with biological systems are relatively unknown.

[22]

However, free nanoparticles in the environment quickly tend to

agglomerate

and thus leave the nano-regime, and nature itself presents many nanoparticles to which organisms on earth may have evolved immunity (such as

salt

particulates from

ocean

aerosols

,

terpenes

from plants, or dust from

volcanic

citation needed ]. A fuller analysis is provided in the article on nanotechnology. eruptions)[]. A fuller analysis is provided in the article on nanotechnology.

San Francisco Chronicle , "Animal studies have shown that some nanoparticles can penetrate cells and tissues, move through the body and brain and cause biochemical damage they also have shown to cause a risk factor in men for According to the

testicular cancer

. But whether cosmetics and sunscreens containing nanomaterials pose health risks remains largely unknown, pending completion of long-range studies recently begun by the

FDA

and other agencies."

[23]

Diesel nanoparticles have been found to damage the cardiovascular system in a

mouse model

.