- Melanin cells
provide skin, hair and eyes their characteristic color and have UV
- A research team
from WC San Diego has developed nanoparticles that mimic melanin cells and
protect skin cells from harmful UV rays.
- The use of these
synthetic melanin nanoparticles in sunscreen is to offer protection which
is closest to that provided by the
naturally occuring melanin.
has been developed by UC San
Diego's material scientists, chemists and nanoengineers. The nanoparticles used
in the sunscreen mimic the naturally occurring melanosomes or the melanin producing
cells, that protect the cells of the body from
damage that can be caused due to the sun's UV rays. The study that holds
promise in protection against the UV rays was published in the journal ACS Central Science
San Diego's professor of nanoengineering, chemistry, material science and
biochemistry said that the scientists were successful in developing a synthetic
version of the nanoparticles used by the body to synthesize and store melanin.
Experimental studies showed that these nanoparticles mimicked the functions of
the naturally occurring melanosomes.
‘Melanin cells have UV protection ability that are mimicked by nanoparticles which are used for making ‘natural’ sunscreen.’
production of melanin in the body is not only beneficial as a sun protectant
but the defects in the production could lead to diseases like albinism and
is a condition in which the immune system
begins to treat the melanocytes as foreign and mounts an immune response. In
albinism, however, genetic mutation results in improper secretion of
tyrosinase, which is a copper containing enzyme associated with the synthesis
of melanin. Vitiligo and albinism
are both conditions that are found to
increase the risk for cancer and there are no known treatment methods.
Gianneschi stated that the high prevalence of diseases associated with improper
melanin production, along with an interest in developing polymeric materials
that were similar to melanin, encouraged the research team to develop melanin
What is Melanin?
is responsible for the color of our skin, hair
and eyes. This is produced by the body by different cells in different animals, for example in the skin of reptiles and in the feathers of birds.
are constantly exposed to UV rays in our daily lives,, which affects the
function and survival of cells in the body. Skin pigmentation is important for
photoprotection, as melanin, besides being a UV absorbent, is also known to
have an antioxidant with radical scavenging functions. Earlier studies have
shown that people with darker skin have a lower incidence of skin cancer when
compared with individuals who have lighter skin.
the benefits of melanin are well known, it is difficult to isolate melanin and
it is easier to synthesize it. The research team led by Gianneschi, developed nanoparticles that were synthetic melanin, and which were found to mimic the natural melanin that were found
in the feathers of birds.
scientists believed, that the novel melanin
like nanoparticles would be taken up by keratinocytes, as they resembled the melanosomes that were found naturally. The
keratinocytes are the most commonly found cells that are present in the outer
layer of the skin, the epidermis.
normal circumstances, the melanin that is produced by the body is secreted as
melanosomes from the melanocytes and is transported to the keratinocytes. The
melanin like nanoparticles that were developed by the research team from UC San
Diego scientists using spontaneous dopamine oxidation, were synthetic analogues
of melanosomes that occurred naturally. The scientists then focused on the
following characteristics of the nanoparticles in tissue cultures:
- UV protection
study found that:
- the synthetic
nanoparticles that were developed by the scientists were taken up by the
- they were
distributed like normal melanocytes
- these nanoparticles
protected the skin cells from DNA damage
findings of the study showed that these specially designed nanoparticles have
the potential to be used as artificial melanosomes. Diseases that are caused
due to defective production of melanin could soon be treated using these
synthetic melanin nanoparticles.
Differences in Skin Pigmentation
differences that occur in the skin pigmentation across ethnicities, are not due to the number of melanocytes that are present in the
skin, but are based on
- the difference in
the melanogenic activity
- the type of melanin
produced in melanosomes
- the number and size
- the melanin content
range from 17.9% to 72.3%
number of melanocytes that are present in the skin of an individual are
dependent on the race and vary across the different sites of the body. It
varies between 2000m2
in the head to 1000 mm2
armpits. The total number of melanocytes that are present varies only about 2
fold between Asian and white skin, with dark skin having the highest levels of
the mechanism of UV protection afforded by the naturally occurring melanin into
synthetically developed melanin, like nanoparticles,
will ensure better protection against the harsh rays of the sun.
- The Protective Role of Melanin Against UV Damage in Human Skin -
- What gives skin its color? -