微流道電泳中抑制樣品滲漏之研究

Abstract

在微流道電泳中控制流體的流動主要是以電滲流幫浦來作為驅動的力量，樣品在樣品流道及分離流道的交匯處容易會發生滲漏，發生的原因歸咎於樣品本身的擴散及對流的流體力學效應，而為了增加分離時的分離效率及解析度，抑制樣品的滲漏是重要的，所以需要運用無閥門的流體控制技術將樣品在交匯處的區帶最佳化。 實驗中將會引用文獻中兩種抑制樣品滲漏的技術並作討論，第一種是抑制電壓的方式，在分離樣品的步驟時施加電壓於樣品槽及樣品廢液槽使得流道交匯處的樣品滲漏被抑制住，而這個電壓就是最佳的抑制電壓。另外一種是設計窄的樣品管道運用在交匯處，傳統的樣品進樣是在一個深寬比都一樣的管道中進行，一種新的設計是將樣品管道的寬度及深度變窄，使得在未加抑制電壓的情況下分離結果的表現有所改善。 兩種技術運用在微流道電泳上都具有不錯的抑制樣品滲漏的表現，在抑制電壓的系統中，樣品的分離能夠得到不錯的結果，尤其是fluoresce in及FITC也能夠在900 V/cm時得到完全的分離；在窄的樣品管道的實驗之中，雖然樣品在分離上也有不錯的表現，而且在800 V/cm時就能將fluorescein及FITC完全分離，雖然樣品峰在金屬線熱壓的微流體膠片中的對稱性表現不佳，但是亦能證明其抑制樣品滲漏的功能。

In microchip CE controlling fluid flow by electroosmotic pump is an important issue. Sample leakage easily happened at intersection from sample channel to separation channel. Sample leakage was shown to arise from both diffusive and convective hydrodynamic effects. To use valveless control of fluid flow to set a well–defined sample plug is required. It could be increasing resolution and efficiency for separation. Two different techniques of inhibiting sample leakage was experienced and discussed in this study. One is pinched voltage system. In separation step, application of potentials to the sample reservoir and sample waster when intersecting channels could inhibiting sample leakage. It is a optimized voltage of pinched voltage. The other one is Narrow Sample Channel form at intersection when floating type in separation step. Conventional injector with uniform channel deepth and width. A novel injector design using reduced sample channel deepth and width to improve separation performance. For two different techniques for inhibiting sample leakage were shown well in microchip CE. In pinched voltage system, FITC and fluorescein could be separated completely when separation electronic field of 900 V/cm. In Narrow Sample Channel form, last two of laser dyes could be separated in the same conditions and separation electronic field down to 800 V/cm. Even though symmetry of peak was not good when microchannel was made by hot embossing with different size of metal line.