Study of the Effect of Gamma Rays on the Melanin Physical Properties and Its Release from Liposomes

Melanin is the brown pigment found in the leptomeninges and substantia nigra of mammalian brains, the choroid coat and ciliary body of eyes, and the skin and hair. In the current study, the UV absorption spectra (optical densities) of melanin and melanin-loaded liposomes at various concentrations were measured in the U.V, visible spectrum between 200 and 800 nm. A device that is half-mirrored divides each wavelength into two beams of equal intensity. An examination compound container is passed through by the sample beam. Additionally, the molar absorption coefficients of free melanin and liposomes loaded with melanin were calculated before and after being exposed to doses of 0, 3, 5, 20 and 50 Gy of ⁶⁰Co gamma rays. According to the results, the absorption spectrum broadened as concentration increased, and the molar absorption coefficient values increased at low doses before decreasing to their pre-irradiation levels at high doses. These findings enable us to draw the following conclusions: a radioprotector, such as melanin, can block adaptive response and completely remove the effects of low-dose radiation.