生物性單分子電晶體的訊號量測與分析

Abstract

生物性電晶體最早在1962年既已問世，其研究方向多為偵測、感測生物性分子而來瞭解樣本的成份或變化，最大的特點是具備高靈敏度、高選擇性、高特異性還有即時輸出的能力，歷年來在醫藥、生技、食品與環境等諸多領域有相當的發展，形態因著不同的需求而有nanowire、nanotube和thin-film等變化。但是以上的研究以分子的角度來看，所取得的都是大量、為數眾多的樣本，只能得到平均且概略的結果，若是要研究細微的過程與機制，將難以歸納，以致近十年開始往單分子平台發展，為一窺那我們所未知的微觀世界。 在本實驗中著重於單分子電晶體系統的架設與量測，除了從10奈米nano-gap晶元設計、微流道組裝、專一性抗體製作、gap表面奈米金的修飾，最重要的是量測系統的電訊測定，結合Cascade probe station、Keithley 2636及其內部的Data acquisition 系統來屏除外界的雜訊與干擾，我們可以從電訊圖清楚地觀察到：對奈米金有專一性的抗體與電晶體source-drain上奈米金結合的電訊改變，針對這部份做各式參數最佳化的研究，我們發現微流道流速在0.06ml/hour、Drain voltage在0.1~0.5V、Gate voltage在0.5V、基礎Drain current在1E-6 ~ 9E-5安培、serum抗體稀釋倍率在1000X、medium抗體稀釋倍率在100倍時有最佳的量測結果。 而在未來，此平台可以再加入黏有不同酵素分子的第二抗體，讓此平台創造更多更宏遠的契機與發展。

In the world, the first bio –transistor was made in 1962. The majority of research direction were bio-sensor transistors that were sensitive, specifical and outputting in real time. We could find developments of bio transistor in medicine, chemistry, food and environment. In the past, people research it by a huge point of view like nanowires, nanotubes, nanocombs, nanorod and thin films. Those research productions were synoptical and average. People could not understand the real mechanism and fine process. So that single molecule transistor was published and developed rapidly in resent year. Here we propose one single molecule transistor, including design of 10 nm nanogap, microfluidic system establishing, selective antibodies making, gold nanoparticles positioning and signals measuring. Above all, the measuring system assembled Cascade probe station, Keithley 2636 sourcemeter and Data acquisition to prevent disturbance and noise from environment. When gold nanoparticles antibodies (Ab of Au NPs) connect to Au NPs on source-drain electrodes, the drain current can raise clearly and suddenly. If the rate of flow = 0.06 ml/hour, drain voltage = 0.1~0.5V, Gate voltage = 0.5V, the baseline of drain current = 1E-6~9E-5 ampere, dilution ratio of Ab serum = 1000X, dilution ratio of Ab medium = 100X, the data of measuring will have the best results. In the future, expectations of this system are binding secondary Antibodies which carry different enzymes or molecules to develop more and more mechanism or abilities that we do not understand.