黑色素是人體內最普遍的生物聚合物之一，過去的研究顯示黑色素具有對抗自由基、活性含氧分子、腫瘤、蛇毒、病毒和重金屬離子等醫學應用的潛 力，
然而它在生物介質的不可溶解性大大的降低了它可能的療效。在先前的研 究裡，我們開發了用脈衝雷射來進行光粉碎以及長時間攪拌等方式，來進行黑 色素在生物介質中的奈米化和可分散化。經由這樣的方式，黑色素暴露的表面 積增加了好幾個數量級，大幅提升了它的化學與生物作用的效率。作為一個示 範，我們先前已經探究了奈米化黑色素對抗活性含氧分子而保護細胞的應用。 在這篇論文裡，我們將展現使用此奈米化黑色素作為對抗毒性金屬離子的螯合 劑的潛力。
本論文研究了使用奈米化黑色素來做為新型螯合劑的可能性。我們使用感應耦合電漿放射光譜儀 ( ICP-OES)來確認奈米化黑色素的螯合能力，並通過流式細胞儀和 ATP 測量來表現細胞活性。結果表明奈米化黑色素不僅可以螯合金
屬離子，更重要的是，它也可以使得受到鉛離子傷害的細胞進行修復。首先我
們確認了本製程的奈米黑色素確實具有螯合重金屬的能力，然後將奈米黑色素
進行細胞實驗，發現奈米黑色素可以治療已受金屬離子的傷害的細胞，但DMSA 不能，我們猜測奈米化黑色素可以進到細胞中使得細胞吐出已被細胞吞噬的鉛離子，並使得細胞的 ATP 產率上升，此結果表明，奈米化黑色素確實具有作為新型螯合劑的可能。

Melanin is one of the most ubiquitous biological polymer widespread in our body tissue, and it has been shown that melanin has potential
medical functions against free radicals, reactive oxygen species, 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
pulsed-laser photo-fragmentation or by extended mechanical stir.
Through this, the exposed surface area could be increased by many orders of magnitude, dramatically increasing the efficiency of chemical and biological interactions. As a demonstration, we have explored the
efficacy of using the nanonized melanin in protecting cells from reactive
oxygen species.In this master thesis , we will explore the utilization of the nanonized melanin as a chelation agent against toxic metal ions.
In this paper, the possibility of using melanin nanoparticles as a new
kind of chelation agent has been studied. The chelating ability was
characterized by using Inductively Coupled Plasma Optical Emission
Spectrometer ( ICP-OES). The cell viability activity were characterized by using flow cytometer and ATP measurement. Result shows the melanin nanoparticles not only can chelate metal ions, more importantly,
but also can recovery cells from harm of Pb2+ ion. First, the chelation
ability of melanin on Pb2+ was studied. Then nanolized melanin was been utilized to in-vitro experiment. it was found the melanin nanoparticles can cure cells from harm of metal ion, but DMSA can not. We hypothesize that the nanolized melanin could diffuse into the cells to spit out lead-ion which had been swallowed by cells, and increase cells ATP. This result indicates that the nanolized melanin did have the possibility of being a new chelating agent.

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