本研究利用金奈米粒子ㄧ對ㄧ鍵結單一條聚核苷酸，來檢測36個鹼基之DNA片段中的單一核苷酸變異（single nucleotide mutation）。首先，我們使用氫硫基化合物Mercaptoundecanoic acid包覆金奈米粒子表面使其親水化；改質後金奈米粒子於高溫80℃與200 mM鹽溶液中有很好的穩定性，並可穩定保存約十個月。此外，利用固相合成方式使金奈米粒子鍵結單一條聚核苷酸，兩條互補且與奈米金形成一對一鍵結的探針進行雜合反應，會形成二聚體結構，可經由穿透式顯微鏡與動態粒徑分析儀證實此結構的存在。我們以一對一鍵結的金奈米探針來偵測單一核苷酸變異的ssDNA，並與一對多鍵結的金奈米探針進行比較。實驗結果發現，一對一與一對多鍵結的金奈米探針均可清楚辨別單一核苷酸變異，但經多次操作後，也發現一對一鍵結的金奈米探針造成的背景干擾遠比一對多鍵結的金奈米探針來得低。 Water-soluble gold nanoparticles were stabily dispersed in 200mM NaCl solution for ten months by surface modification with mercaptoundecanoic acid. We developed an efficient method to link nanogold with single strain DNA (ssDNA). One to one conjugates of the Au/ssDNA(+) were dimerized with the complimentary Au/ssDNA(-) and imaged by TEM and nanoparticle tracking analysis. Both one to one conjugates of Au/ssDNA and randomly linked Au/ssDNA were able to detect single nucleotide mutation by absorb intensity. The lower background absorb intensity of one to one conjugates can be estimated by the detection results.
