本研究以基因轉殖大腸桿菌進行CdS奈米粒子的製備，研究內容結合生物科技以及奈米技術兩個領域。CdS為擁有直接能隙的II-V半導體材料，粒徑小於6 nm以下時，有明顯的量子侷限效應，被視為新一代的LED發光材料。除此之外，CdS奈米粒子應用於各類感測器以及生物螢光標定中的研究也相當的多。
本研究首次利用基因工程的手法，將gshA及gshB基因片段以重組載體送入細胞中，分別表現glutathione合成酵素γ-GCS及GS，藉此促進大腸桿菌中glutathione的含量，來量產CdS奈米粒子。GSH分子為生物合成CdS奈米粒子之關鍵，其含量之增加有助於細胞生成CdS粒子。我們證實，大腸桿菌ABLE C生成之CdS奈米粒子粒徑介於2~5 nm之間。經過基因轉殖的菌株，細胞中GS合成酵素含量增加，細胞中CdS粒子產量有顯著提升。
粒子特性方面，基因轉殖大腸桿菌所生產的CdS奈米粒子由於粒子表面有較多的GSH包覆，因此在水溶液中分散性更為提升，而重組蛋白的產生對所生成CdS的粒徑無太大影響。在此我們證明了以大腸桿菌生產CdS奈米粒子的可行性，透過基因轉殖細胞能更近一步增進產量和改善產物性質。在實驗過程中，我們也證實了GSH含量的多寡，確實引響細胞生產CdS的能力，對於此系統背後生理機制的釐清也有所助益。

Cadmium sulfide nanoparticles were synthesized intracellularly in gene modified Escherichia coli ABLE C. The nanoparticles, a known semiconducting material, which have unique optical and electronic properties, have potential for application in the emerging field of nanoelectronics. To produce nanomaterial cheaply and efficiently, biological methods of synthesis are being explored. Schizosaccharomyces pombe were found having the capacity to synthesize CdS nanoparticles intracellularly in 1983. Recently, in 2004, Sweeney found that E. coli also have ability to synthesize CdS nanoparticles. Morever, in his study, he pointed out that the cellular glutathione can enhance the formation of nanoparticles. Inspried by Sweeney, we constructed a gene modified E. coli ABLE C which could use for glutathione overproduction and attempt to figure out how this parameter can enhance the synthesis of nanoparticles within bacterial cells. Our results showed that nanoparticles biosynthesis increased about 1.6 –fold in gene modified cells compared to wild type cells. HRTEM data showed that the nanoparticles had a Wurtzite hexagonal lattice structure and most of the nanoparticles were in the size range of 2-5 nm. We also observed that nanoparticles synthesized in gene modified cells were dispersed better in water than these in wild type cells. The well dispersion behavior was due to more glutathione coated on the nanoparticles. To our best knowledge, this is the first report using genetic modification to enhance biosynthsis of CdS nanoparticles and to unravel the siginificance of glutathione in this procedure. By understanding parameters of nanoparticles synthesis, it might be possible to modulate the properties of biosynthesized nanopartilces, such as size, shae, and crystal structure.

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