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Radiotherapy for abdominal and pelvic cancers almost always leads to small-intestine injuries that are difficult to heal, eroding the quality of life of patients. To counteract this, researchers have developed an orally consumable material made from melanin\u2014the pigment in our skin that protects us from ultraviolet rays\u2014that can shield the intestines from ionizing radiation<\/a> (Cell Biomater. 2025, DOI: 10.1016\/j.celbio.2025.100214).<\/p>\n \u201cSome microorganisms in high-dose radiation environments are rich in melanin, which sparked our interest in melanin\u2019s role in radiation protection,\u201d says Wei Cao<\/a>, a professor of chemistry at Beijing Normal University. Cao and his team synthesized selenium-modified melanin nanoparticles (SeMNPs) through the oxidative polymerization of two naturally occurring amino acids: selenocysteine and L-dopa. Selenium is an essential trace element that plays a critical role in the intracellular antioxidant system. Back in 2020, an unrelated group found that selenomelanin-treated cells withstood radiation exposure better than untreated cells<\/a>.<\/p>\n Cao\u2019s group found that SeMNPs adequately tolerate gastric juices and intestinal enzymes for up to 6 h. When the researchers incubated human cells with SeMNPs and irradiated them, the nanoparticles protected the cells, suppressed the generation of superoxide free radicals, scavenged reactive oxygen species that cause cell damage, and relieved cell-cycle arrest due to radiation-induced DNA damage.<\/p>\n To gauge the radioprotective strength of the SeMNPs, the researchers injected them intraperitoneally into mice and then subjected the animals to whole-body radiation. All the mice who received injection survived for 30 days, while 80% of those who weren\u2019t injected died within 6 days.<\/p>\n The researchers also fed mice some SeMNPs before irradiating their whole body. Examination of their intestines after 7 days showed relatively healthy tissues with reduced DNA damage. Analysis of intestinal proteins showed that SeMNPs had suppressed inflammatory pathways, and the gene expression profile was almost similar to that of nonirradiated intestines.<\/p>\n Current radioprotection drugs like amifostine and palifermin are not suited for protecting the gut because they must be injected, have short half-lives, and have poor stability. That\u2019s why an orally administered molecule that can withstand the harsh environments of the stomach and intestines could be so valuable.<\/p>\n