New biomaterial could shield against harmful radiation

Short form: a synthetic version of melanin – the pigment that darkens human skin – containing selenium has been found to protect organisms from dangerous levels of ionizing radiation (X-rays here). The researchers suggest that astronauts could apply it like sunscreen while in deep space.

OK… but… wouldn’t a sunscreen made of some simple paste mixed with selenium work just as well, rather than going the extra steps in cobbling together the specific melanin pigment? I suppose if astronauts could be modified somehow so that if they were fed a diet higher in selenium, or took selenium supplements, and the selenium bonded to the melanin in their skin, that might work, but that doesn’t seem to be what they’re working towards. Hell, couldn’t the selenium be formed into fabric and worn as clothes? I remain baffled about the mechanism by which a small amount of selenium bonded to a form of melanin protects the body from radiation. You’re madding perhaps grams-per-square-meter of selenium to your skin, where X-Ray technicians wear lead aprons that are thousands of times more massive to provide protection.

But, ok, sure. let’s go with it and assume that it works. One detail not in evidence is what does selenomelanin *look* like? I would assume that it doesn’t look like standard melanin. Rather than astronauts looking darker after getting their selenomelanin coatings or boosters… would they look gray? Green? Silver? Magnesium oxide white?