Sun creams Many sun creams use nanoparticles. These sun creams
are very good at absorbing radiation, especially ultraviolet
radiation. Owing to the particle size, the sun creams
spread more easily, cover better and save money because
you use less. The new sun creams are also transparent,
unlike traditional sun creams which are white. The use of
nanoparticles is so successful that they are now used in more
than 300 sun cream products.
Some sun creams contain nanoparticles of titanium oxide.
Normal-sized particles of titanium oxide are safe to put on
the skin.
It is thought that nanoparticles can pass through the skin
and travel around the body more easily than normal-sized
particles. It is also thought that nanoparticles might be toxic
to some types of cell, such as skin, bone, brain and liver cells.
a i How is the size of nanoparticles different from
normal-sized particles of titanium oxide?
ii Suggest how the size of nanoparticles might help
them to enter the body more easily.
b Give two advantages of using nanoparticles in sun
creams.
c Why might nanoparticles be dangerous inside the
body?