Study: Melanin-covered nanoparticles could prevent radiation damage
Melanin-covered nanoparticles provide a novel approach to protection of bone marrow from ionizing radiation based on prevention of free radical formation by melanin, according to research published online April 24 in the International Journal of Radiation Oncology, Biology and Physics.

Ekaterina Dadachova, PhD, associate professor of nuclear medicine and of microbiology and immunology at Albert Einstein College of Medicine in Bronx, N.Y., and colleagues hypothesized that melanin, which protects against radiation is insoluble and could be delivered to the bone marrow by IV-administrated melanin-covered nanoparticles.

Polymerization of melanin precursors on the surface of silica nanoparticles resulted in formation of a 15-nm [nanometers] thick melanin layer as confirmed by light scattering, transmission electron microscopy and immunofluorescence, wrote Dadachova and colleagues.

The researchers found that these particles successfully lodged in bone marrow after being injected into mice. Systemic melanin-covered nanoparticles administration reduced hematologic toxicity in mice treated with external radiation or radioimmunotherapy, whereas Dadachova and colleagues did not observe any radiation protection.

"The ability to protect the bone marrow will allow physicians to use more extensive cancer-killing radiation therapies and this will hopefully translate into greater tumor response rates," said Arturo Casadevall, MD, PhD, professor of medicine and of microbiology & immunology at  Einstein and a co-author of the study.

Dadachova predicts that clinical trials testing whether melanized nanoparticles might protect cancer patients undergoing radiation therapy could begin in two to three years. She also noted that melanized nanoparticles might also have other applications, such as protecting workers charged with cleaning up nuclear accidents, protecting astronauts against radiation exposure in space, or even protecting people following a nuclear attack.