金奈米棒的製備改質與Tau蛋白感測應用

金奈米顆粒在近年來備受關注的應用為生物感測技術開發應用，金奈米顆粒的光學性質能隨著不同的大小、形貌、組成、結構、及微環境而改變，也照成表面電漿共振 (surface plasmon resonance, SPR) 吸收波長的改變，因而造成金奈米顆粒的顏色的改變，而成為比色法生物感測的應用原理。而這類分析方法因為不需仰賴貴重儀器而有潛力能為簡單易用低成本的分析方法。　　本研究選用表面電漿共振調控範圍最大的金奈米棒來進行Tau蛋白生物感測的應用，成功利用兩步驟合成法與本實驗改良的一步驟成長法，利用穿透式電子顯微鏡影像確認金奈米棒長約50 nm、寬約15 nm、可見光-近紅外光吸收光譜觀察到長軸吸收峰在800 nm，精簡傳統的晶種溶液合成的步驟而能經濟地合成金奈米棒。在參數探討方面，硝酸銀濃度在100至120 M時可合成出具最佳品質的金奈米棒。成長溶液中的晶種濃度的差異主要是影響金奈米棒短軸的過成長程度，較高的金前驅物對晶種濃度有較長的短軸長度。而在時間參數比較了在兩步驟成長法與一步驟成長法在初始的差異，發現一步驟成長法在硼氫化鈉水溶液添加之後約15分鐘開始觀察到金奈米棒明顯地成長，與兩步驟成長法一加入金晶種溶液立即成長之反應機制有所不同。而在金奈米棒長時間的光譜演化中發現過量的抗壞血酸會抑制藍位移的現象。金奈米的應用關鍵步驟為金奈米棒的表面修飾，在此利用FT-IR、XPS與表面電位(Zeta potential)比較了 11-巰基十一酸(11-Mercaptoundecanoic acid, MUA)與胱胺(cystamine)和二硫代琥珀酰亞胺基丙酸酯 (dithiobis[succinimidylpropionate], DSP)的修飾結果。最後修飾anti-Tau抗體對Tau蛋白進行感測實驗，探討金奈米棒邊對邊(side-by-side)與頭接尾(end-to-end)結合組裝時對表面電漿共振吸收光譜的差異。

關鍵字

金奈米棒；表面電漿共振；生物感測器； Tau蛋白

並列摘要

Gold nanoparticles (AuNPs) have been attracted much attention over the past decades because they have a wild variety of applications in biological sensing. Depending on their size, shape, composition, structure, and local environment, AuNPs can show different characteristics especially the surface plasmon resonance (SPR) property. SPR can observe the color changed that reflect the underlying coherent oscillations of conduction band electrons of particle under the irradiation with the light of fitting wavelengths. These electrons (plasmons) bring the different intensities of absorption and scattering of light, and from the basis to design many biological sensing applications of AuNPs. 　In this study, Au nanorods was synthesized using a simple and low cost method and then were used for biosensing applications because the morphology of Au nanarods have the wide SPR absorption range which can be adjust by aspect ratio. We have successfully developed one-step growth method to improve the efficiency of Au nanorods by comparison with traditional two-step growth method. The average diameter of gold nanorods was 50 nm in length and 15 nm in wide, which was confirmed by TEM images, and the SPR absorption position was located 800 nm. Without the seed solution synthesis step, we can more efficiently and greenly to prepare gold nanorods solution. In addition, several parameters were selected to optimize the growth of Au nanorods. We found that silver nitrate (AgNO3) of 100~120 M could fabricate good morphology for gold nanorods growth solution. The Au seed concentration of growth solution is related to the overgrowth process and the short axis of Au nanorods increased with the increase in gold precursor to seed ratio from 208 to 13333. In contrast to the two-step growth method which the gold nanorods appeared just after the addition of Au seed solution, one-step growth method needed to wait 15 minutes for nuclei formation. In addition, high concentration of ascorbic acid can inhibit blue-shift of Au nanorods. After the optimization, Au nanorods were surface modified with several organics for Tau protein detection. Results of FT-IR, XPS and Zeta potential identified that 11-Mercaptoundecanoic acid, cystamine, and dithiobis[succinimidylpropionate] ( DSP) can be used as the modifiers for Tau protein detection. Later, we used linker to modify anti-Tau antibody for Tau protein sensing and the influence of end-to-end and side-by-side aggression of Au nanorods on how the sensitivity of Tau protein detection was evaluated.

並列關鍵字

gold nanorods ； surface plasmon resonance ； biosensor ； Tau protein

參考文獻

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金奈米棒的製備改質與Tau蛋白感測應用

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