Gentler, safer hair dye based on synthetic melanin

With the coronavirus pandemic temporarily shuttering hair salons, many clients are appreciating—and missing—using hair dye to cover up grays or touch up roots. Whether done at a salon or at home, frequent coloring, however, ...

Melanin-producing Streptomyces are more likely to colonize plants

Plant growth-promoting Streptomyces assemble into the internal, root endophytic compartments of a wide variety of plants around the world. These bacteria are well-known for their ability to produce a huge array of secondary ...

Black nanoparticles slow the growth of tumors

The dark skin pigment melanin protects against the sun's damaging rays by absorbing light energy and converting it to heat. This could make it a very effective tool in tumor diagnosis and treatment, as demonstrated by a team ...

Researcher uses decomposition fungi to create patterns in wood

Fungi that decompose tree trunks can conjure up real works of art in wood. In nature, however, the decay-causing fungi not only decorate the tree, but also destroy it. Empa researchers are now teaching the fungi how to draw. ...

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Melanin

Melanin i/ˈmɛlənɪn/ (Greek: μέλας, black) is a pigment that is ubiquitous in nature, being found in most organisms (spiders are one of the few groups in which it has not been detected). In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms. All melanins can be considered as derivatives of polyacetylene, since they rely on a polyconiugate structure. Another common form of melanin is pheomelanin, a red-brown polymer of benzothiazine units largely responsible for red hair and freckles. The presence of melanin in the archaea and bacteria kingdoms is an issue of ongoing debate among researchers in the field.

The increased production of melanin in human skin is called melanogenesis. Production of melanin is stimulated by DNA damage induced by UVB-radiation, and it leads to a delayed development of a tan. This melanogenesis-based tan takes more time to develop, but it is long-lasting.

The photochemical properties of melanin make it an excellent photoprotectant. It absorbs harmful UV-radiation (ultraviolet) and transforms the energy into harmless heat through a process called "ultrafast internal conversion". This property enables melanin to dissipate more than 99.9% of the absorbed UV radiation as heat (see photoprotection). This prevents the indirect DNA damage that is responsible for the formation of malignant melanoma and other skin cancers.

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