Chelation of Toxic Metal Ions by Nano-Melanin
Yi-Cheng Liu1,4*, Hsiang-Wei Hsu2, Jia-Liang Yen3, Hoang-Yan Lin1, Szu-yuan Chen2,3,4
1Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
2Department of Physics, National Central University, Jhongli 32001, Taiwan
3Graduate Institute of Biophysics, National Central University, Jhongli 32001, Taiwan
4Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
* presenting author:Yi-Cheng Liu,
Melanin is one of the most ubiquitous heterogeneous biological polymer widespread in our body tissue and it has been shown that melanin has potential medical functions against free radicals, reactive oxygen species (ROS), tumor, venin, virus, and heavy metal ions. However, its insolubility drastically reduces its efficacy. We have shown previously that melanin can be broken down to become nanometer-sized and water-dispersible by mechanical stir. Therefore, the exposed surface is increased by many orders of magnitude, dramatically increasing the efficiency of chemical and biological interactions. In this work, we explored the utilization of the nanonized melanin as a chelation agent against heavy metal ions. The binding capacity of nanonized melanin exposed to various conditions of Pb2+ was evaluated. It was found that nanonized melanin processed by mechanical stir exhibited a much stronger effect than the previous work processed by oxidative polymerization on binding heavy metal ions. This could be ascribed to the exceptional surface-to-volume ratio of our approach.

Keywords: melanin, nano-medicine, water-dispersible, metal ions, chelation