The effect of preparation procedures on the interaction of melanin with ionizing radiation

Melanin, a pigmented biopolymer found in most vertebrates and invertebrates, has many unique properties, including radioprotection. Studies have shown that melanin-covered nanoparticles can be used to protect tissues against radiotoxicity during radioimmunotherapy. In this study we explore the radioprotective properties of melanin using different preparation procedures. Melanin samples from the ink sac of Sepia officinalis were purified using different centrifugation conditions. The pellet was then collected and its X-ray absorption was tested. Our experimental results show that the percentage of X-ray blocking by melanin depends upon the centrifugation force used during the sample preparation. The maximum amount of X-ray blocking occurs when the melanin sample is prepared at 2875g. We conclude that the preparation procedures significantly affect the radioprotective properties of melanin. This finding may be important for applications, such as the use of melanin as a lightweight radiation-protective material.