本篇論文主要在報告利用耐輻射奇異球菌Deinococcus radiodurans IR產生金屬銀奈米材料並推測可能的生成機制。在整個實驗過程中，我們發現在靜止期的D. radiodurans IR菌液加入硝酸銀反應數小時後可以在光學顯微鏡下觀察到有黑色線狀物質及黑色顆粒產生附著在細胞聚集成的團塊上，該線狀物質經過X光能譜儀（Energy dispersive X-ray spectrometer, EDS）分析確認成份為元素銀，且這些線狀物質在紫外光/可見光光譜中約350 nm附近具有特性吸收。這些銀奈米線的平均寬度約60到100 nm，最長長度可以超過100 □m。在實驗過程中我們也嘗試了一些還原電位頗高的金屬離子，如金（III）和銅（II）試圖了解細胞聚集現象與金屬離子還原電位的關係及相同的反應條件是否適用於其他金屬離子。若將細菌固定在晶圓表面後，利用類似的反應條件可使部分細胞之間被銀線連結甚至形成網絡。這些在細胞之間的奈米銀線（silver nanowires）生長可以受到兩側的細胞影響而產生彎曲，透過這樣的方式可以間接了解在菌液中細胞團塊上銀線可能的生長方式，以及知道D. radiodurans IR在懸浮反應系統中奈米銀線如何從細菌細胞上起頭。

In this thesis, we report a novel method using Deinococcus radiodurans IR culture to fabricate silver nanostructures, including nanoparticles and nanowires, and discuss the hypothetical mechanism of their formation. After series of experiments, we found that these black wires and particles only exist in stationary phase cultures. These black wires are metallic silver after being analyzed by energy dispersive X-ray spectrometer, and the size of them is from 60 to 100 nm in width. Furthermore, as we immobilize cells on wafer surface, silver nanowires also exist and connect at least one cell. Even more, there are silver nanowire network connecting several cells, too. Straight and curved silver nanowires are observed and the curvature is formed through influence of certain effecter cells beside the wire. We also tested some heavy metal ions, such as gold (III) and copper (II), to know what the relationship between cell aggregates formation and reduction potential is and to see if same condition can be applied to other metal ions. In conclusion, we believe that D. radiodurans IR culture could be a very efficient system to fabricate silver nanostructures and silver nanowire networks.

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