光柵結構之表面電漿柯爾磁光增強效應整合微流體晶片系統應用於生醫感測

在本研究中，我們主要在金光柵表面電漿(SPR)系統下，加入鐵磁性材料形成金/鐵/金之三明治結構，以提升橫向磁光柯爾效應(TMOKE)的表面電漿增強現象，並應用於非標定、高敏感度的光學生物量測。經材料選擇與結構尺寸優化，而後整合PDMS微流道系統封裝；其中包含微泵浦(micropump)及閥門(normally-close valves)等動件並加入PDMS稜鏡設計降低反射雜訊，成一32×22 mm2的自動化生醫感測晶片。我們分析了元件特性及生物量測的能力，其最大磁光訊號約為0.04 且能觀察到磁光訊號在共振波長附近對環境折射率具有相當高的靈敏度。首先透過整合好的磁光感測晶片來量測不同濃度的蔗糖水溶液，所測得之本質解析度與蔗糖水(bulk solution)的最小解析濃度分別約為1.47×10-6 RIU與0.007%(wt)；之後利用高親和力的avidin/biotin生物組合做動態(real time)量測：預先將biotin透過BSA標定接於元件金表面，後通入不同濃度之avidin驗證表面電漿磁光訊號對表面附近之生物檢體具有線性量測與定量分析的特性，計算得出avidin 之解析度約為31nM。

關鍵字

微流體；生醫感測；表面電漿光柵；磁光柯爾效應

並列摘要

In this thesis, a high-sensitivity biosensor is demonstrated by exploiting surface plasma(SP) enhanced transverse magneto-optical Kerr effect(TMOKE). The size of the device is 32×22 mm2 with the prism, microfluidic system and ferromagnetic plasmonic grating integrated on a single chip with the ability to deliver and detect bio-agents systematically. The SP grating made on an optimized composite Au/Fe/Au layer exhibits a very dispersive Kerr Parameter variation near the surface plasmon resonance wavelength. After the fabricating process, we characterized the magneto optical effect of the composite ferromagnetic grating and the capabilities for detecting bio-molecules. The maximum of measured Kerr signal is about 0.04 with convert factor of 0.087 nm-1. Through this integrated system, we have demonstrated the detection of sucrose solution in low concentrations. The calculated resolution for bulk solution is about 10-6 RIU, corresponding to a minimal concentration of 0.007 %(wt). Moreover, a preliminary experimental result on studying avidin biotin interaction was also shown. The sensitivity of avidin detection in PBS solution is about 31 nM, which is limited by the fluctuation of flowing media during measurement. The whole system is potential to accomplish a compact, noncontact optical detection scheme.

並列關鍵字

microfluidics ； biosensor ； surface plasmonic grating ； magneto-optical Kerr effect

參考文獻

[1] R. W. Wood, "On a remarkable case of uneven distribution of light in a diffraction grating spectrum," Philosophical Magazine, vol. 4, pp. 396-402, Jul-Dec 1902.

[2] U. Fano, "The Theory of Anomalous Diffraction Gratings and of Quasi-Stationary Waves on Metallic Surfaces (Sommerfeld’s Waves)," Journal of the Optical Society of America, vol. 31, pp. 213-222, 1941.

[3] R. H. Ritchie, E. T. Arakawa, J. J. Cowan, and R. N. Hamm, "Surface-Plasmon Resonance Effect in Grating Diffraction," Physical Review Letters, vol. 21, pp. 1530-1533, 1968.

[4] E. A. Stern and R. A. Ferrell, "SURFACE PLASMA OSCILLATIONS OF A DEGENERATE ELECTRON GAS," Physical Review, vol. 120, pp. 130-136, 1960 1960.

[5] E. Kretschmann and H. Raether, "Notizen: radiative decay of non radiative surface plasmons excited by light," Zeitschrift für Naturforschung A, vol. 23, pp. 2135-2136, 1968.

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光柵結構之表面電漿柯爾磁光增強效應整合微流體晶片系統應用於生醫感測

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