探討在奈米微流道中蛋白質吸附對電滲流的影響

Abstract

電驅動奈米流道已經被廣泛的利用在許多生化分析的系統上，尤其在尺度更微小、因而較難以控制的蛋白質分析上。雖然人們對蛋白質本身的生化結構已有深入的認知，然而許多蛋白質如何在奈米流道的行為仍是未知，例如，蛋白質如何吸附道流道表面上，和蛋白質如何影響流道的電滲流(electro-osmotic flow)傳輸。這份研究利用電流監控法(current-monitoring method)來量測奈米微流道(高度約500奈米)中電滲流移動率(electro-osmotic mobility)在不同濃度的牛血清白蛋白(bovine serum albumin: BSA)下的表現。我們發現電滲流移動率會隨著蛋白質濃度的增加而下降，此下降趨勢並非無限制延伸到零，而是達到一個飽和值。藉由和隨機序列吸附模型(random-sequential-adsorption model)的指數函數比對下，可以得到造成移動率變化的特徵濃度為1.4±0.3mg/ml，而移動率的飽和值為1.3±0.1 cm*um/V s.

Electrokinetically-driven nanofluidics has been widely used in micro-total-analysis system (μTAS), especially for proteomic analysis. However, many details in how proteins were absorbed onto the surface and perturbed the electro-osmotic flow (EOF) are still elusive. In this study, we investigated the reliability of current-monitoring method by reproducing the results under different conditions, and used this method to measure electro-osmotic mobility under different concentration of bovine serum albumin (BSA) in nano-slits (channel height ~ 500nm). We observed that EOF mobility would be reduced as BSA concentration increases, and reach a saturation level at high BSA concentration. By fitting with exponential decay from random-sequential-adsorption model suggested by Adamczyk et al1,2, two relevant parameters were found: characteristic perturbing concentration is 1.4±0.3 mg/ml and mobility at high concentration is 1.3±0.1 um*cm/V s.