電滲透流對電荷可調節之錐型奈米孔道中離子傳輸行為之影響

Abstract

近年來，由於生醫材料的蓬勃發展，奈米裝置用於DNA序鏈鑑測及蛋白質膜分離受到高度地關注。基於此，吾人以理論分析來探討藉由調控電解質液中pH值對離子電流整合效應的影響。不同於以往研究中大多忽略電滲透流對於離子電流整合效應的影響，吾人結合Poisson、Nernst-Planck、與Navier-Stokes方程式探討電滲透流在貼近真實生物膜上孔道的帶電方式下的行為。藉由調整pH值、離子濃度及施加的電壓，吾人進而探討仿生細胞通道內的離子電流整合效應影響。數值模擬的結果顯示，電滲透流在適當的離子濃度、pH值遠離等電位點、施加高電壓下時會有顯著地影響。在與以往研究中忽略電滲透流效應的結果比較下，偏差值之數量級可達100%。此外，無論在示性或示量上，考慮電滲透流皆造成與以往研究有很大的不同，此研究可以提供給往後實驗者在實驗裝置設計上的參數調整參考。

Due to the rapid progress in biomedical materials in the past decades, the application of nano devices in DNA sequencing and membrane separation of proteins has drawen the attention of researches in various fields. Inspired by this, we analyze theoretically the influence of solution pH on the ion current rectification (ICR) behavior in a pH-regulated nanopore. Different from those in previous studies, where the effect of electroosmotic flow (EOF) is neglected, we solve simultaneously the Poisson, Nernst-Planck, and Navier-Stokes equations describing the behavior of a biomembrane, so the problem considered is closer to reality. Through adjusting the solution pH, ionic concentration, and the applied electric potential bias, we examine the ICR phenomenon under various conditions. The results of numerical simulation reveal that the influence of the EOF effect on ICR can be significant if the ionic concentration takes a medium high value, the solution pH is far from the isoelectric point, and the applied electric potential bias high. We show that the conventional result, where EOF is neglected, the percentage deviation in the rectification factor (RF) can be on the order of 100%. In addition, EOF is capable of influencing both qualitatively and quantitatively RF. Our analysis provides valuable information for designing experimental devices and selecting relevant parameters.