利用矽奈米線場效電晶體對鉀離子的偵測

近幾十年來，矽奈米線（silicon nanowire, SiNW）成為學術界及業界積極研究的對象並且被應用在許多方面，包括p-n 二極體（p-n diode）、埸效電皛體（field-effect transistor）和邏輯閘（logic gate）。矽奈米線場效電晶體（silicon nanowire field-effect transistor, SiNW-FET）擁有超靈敏度（ultrasensitive）、即時反應（real-time response）、臨場（in situ）以及免標定偵測（label-free detection）等優點，相當有潛能發展為生物感測器（biosensor）。矽奈米線場效電晶體可應用於離子選擇場效電晶體（ion-selective field-effect transistor, ISFET）。其源極和汲極之間的電流變化是源自於離子與離子載體（ionophore）結合時所引起電場的變化，離子產生的影響相當於閘極，造成源極和汲極之間的電流變化。纈氨黴素（valinomycin）是存在於大自然中的中性離子載體，為一種破壞細胞內外鉀離子濃度梯度的神經毒素。相對於其他離子而言，纈氨黴素對於鉀離子擁有相當大的結合常數（binding constant），而鉀離子在神經傳導和細胞胞吐（exocytosis）過程中扮演著重要的角色，因此在離子選擇場效電晶體上修飾纈氨黴素，有潛力偵測在神經傳導和細胞胞吐過程中存在的鉀離子。目前文獻所記載纈氨黴素和鉀離子的結合常數大多是在有機溶液系統，然而在生物界，絕大多數纈氨黴素和鉀離子存在於水溶液，因此本論文將利用經纈氨黴素修飾過後的矽奈米線場效電晶體探討纈氨黴素和鉀離子在水溶液中的結合常數及其選擇性。

關鍵字

單晶結構矽奈米線；場效電晶體；纈氨黴素；結合常數；選擇係數

並列摘要

In the past decades, silicon nanowires （SiNWs） have been intensively studied, because they are excellent candidates for a variety of applications. In particular, SiNWs-based field-effect transistor （SiNW-FET） can be used as chemical and/or biological sensors taking advantages of their ultrasensitivity, real-time response, and label-free detection. In the sensing applications, SiNW-FET has been employed as ion-selective field-effect transistor （ISFET）, where a selective ionophore was modified on the surface of the SiNW-FET to detect a specific ion. The conductance change inside the ionophore-modified SiNW-FET depends on the electric field exerted from the ion-ionophore complex, which plays the role of a ionic gate to the FET-based device. Because of the considerably large binding constant between valinomycin and potassium ion （K+）, valinomycin-modified SiNW-FET was fabricated in this study to detect K+ in aqueous solution. The binding constant between valinomycin and K+ is determined from a model fitting to the measured curve of conductance change versus K+ concentration. This valinomycin-modified SiNW-FET is suitable for quantitative analysis and will be applied to monitor the extracellular ionic fluctuation in the future.

並列關鍵字

single crystalline silicon nanowire ； field-effect transistor ； valinomycin ； binding constant ； selectivity coefficient

參考文獻

David A. LaVan, Tarek M. Fahmy, Mark A. Reed, Nature

Tarek M. Fahmy, and Mark A. Reed, Nano Letters 2007, 7,

47. Liu, Q. X.; Wang, C. X.; Xu, N. S.; Yang, G. W.,

10. Lieber, C. M.; Wang, Z. L., Material Research Society

C.; Lieber, C. M.; Wang, Z. L., Nano Letters 2004, 4,

國際替代計量

利用矽奈米線場效電晶體對鉀離子的偵測

主題瀏覽