應用奈米粒子自組裝輔助電擊穿產生奈米裂縫於蛋白質濃縮

在檢測之前，將樣本預先進行濃縮以提高濃度進而增加檢測的準確性是相當重要的一個步驟，尤其在低濃度的蛋白質檢測中，更顯得濃縮步驟的必要性。本研究旨在利用金奈米粒子降低PDMS產生奈米裂隙所需之電擊穿電壓以達到濃縮蛋白，其晶片母模與晶片分別利用黃光微影製程製作，晶片母模設計單層十字形流道，並以PDMS進行圖形轉印，其中兩側設計特定位置PDMS結構阻隔微米流道，晶片則使用APTES(3-aminopropyl-triethoxysilane)進行表面修飾，再將金奈米粒子自組裝(self-assembly)在晶片上，再藉由施加電壓於結構兩端，產生電擊穿現象製造出奈米通道連接微米流道。本研究根據不同濃度的金奈米自組裝在晶片上，測試出可有效降低電擊穿所需之電壓的參數，以濃度0.5 nM的金奈米自組裝晶片效果最佳，能將電壓從1050 V降低至500 V，實驗更進一步針對1 nM螢光異硫氰酸素 (Fluorescein Isothiocyanate, FITC) 標示之胎牛血清蛋白 (Bovine Serum Albumin, BSA) 進行電動力濃縮至30分鐘時提升1.5×104的濃度，順利將1 nM FITC-BSA提升至15 M。本研究所製作的濃縮晶片不僅製程方便、低成本、更快速且維持高倍率的濃縮效率。

關鍵字

排斥集中效應；奈米粒子；自組裝薄膜；預濃縮；電擊穿

並列摘要

Preconcentration is an essential step in increasing the accuracy of subsequent detection, particularly for samples of extremely low concentrations. Because of overlapping electrical double layers in the nanofluidic channel, the concentration polarization effect can be generated by applying an electric field. Therefore, a nonlinear electrokinetic flow is induced, resulting in the fast accumulation of proteins in front of the induced ionic depletion zone, the so-called “exclusion-enrichment effect.” Nanofissures were created in this work to preconcentrate proteins by applying the exclusion-enrichment effect. The protein sample was accumulated and stacked at a specific location while the depletion force was balanced by the electroosmotic force. The preconcentration chip for proteins was fabricated using simple standard soft lithography with a polydimethylsiloxane (PDMS) replica. Nanofissures were formed by utilizing the self-assembly of gold nanoparticle-assisted electric breakdown. The proposed method for nanofissures formation, which involves using self-assembled monolayers (SAMs) of nanoparticles at the junction gap between microchannels, substantially decreases the required electric breakdown voltage. The experimental results indicate that a protein sample with an extremely low concentration of 1 nM was concentrated to 1.5×104-fold in 30 min by using the proposed chip.

並列關鍵字

Exclusion-Enrichment Effect ； Self-assembled monolayer ； Preconcentration ； Protein ； Electric breakdown

參考文獻

[1] C. C. Lin, J. L. Hsu, and G. B. Lee, "Sample preconcentration in microfluidic devices," Microfluidic and Nanofluidic, vol. 10, pp. 481-511, 2011.

[2] Y. Mourzina, D. Kalyagin, A. Steffen, and A. Offenhausser, "Electrophoretic Separations of Neuromediators on Microfluidic Devices," Talanta, vol. 70, pp. 489-498, 2006.

[3] D. Ross and L. E. Locascio, "Microfluidic Temperature Gradient Focusing," Analytical Chemistry, vol. 74, pp. 2556-2564, 2002.

[4] B. Grass, R. Hergenroder, A. Neyer, and D. Siepe, "Determination of Selenoamino Acids by Coupling of Isotachophoresis / Capillary Zone Electrophoresis on a PMMA Microchip," Journal of Separation Science, vol. 25, pp. 135-140, 2002.

[5] D. Wu and A. J. Steckl, "High Speed Nanofluidic Protein Accumulator," Lap on a Chip, vol. 9, pp. 1890-1896, 2009.

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應用奈米粒子自組裝輔助電擊穿產生奈米裂縫於蛋白質濃縮

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