离子液体电解质对DNA穿过α-溶血素纳米孔的影响  

Investigation of Single-stranded Deoxyribonucleic Acid Translocation Through α-Hemolysin Nanopore with Ionic Liquid Supporting Electrolytes

作　　者：孙珊珊 刘元敏 李光宇 吴志勇 SUN Shan-Shan, LIU Yuan-Min, LI Guang-Yu, WU Zhi-Yong(Research Center for Analytical Sciences （ RCAS）, Department of Chemistry, College of Sciences, Northeastern University, Shenyang 110819, China)

机构地区：[1]东北大学理学院分析科学研究中心,沈阳110819

出　　处：《分析化学》2018年第6期858-864,共7页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(No.21575019);辽宁省自然科学基金项目(No.LZ2015036)资助~~

摘　　要：不同碱基的DNA分子空间占位和带电状态存在差异,其通过单个纳米孔时可引起特征性的电流脉冲变化,有望成为新一代单分子测序方法。然而,常规条件下DNA分子穿过纳米孔的速度很快(10^(-2)s),引起的电流变化小(pA级),因此分子亚结构信息的准确获取对现有仪器设备的性能提出了极高要求。本研究在α-溶血素纳米孔的两端分别引入高粘度和离子导电性较好的离子液体支持电解质,以构建粘度梯度体系,并对溶液的酸度进行优化,以期对ss DNA穿孔行为进行调控。初步的研究结果表明,在trans端为纯离子液体Bmim PF_6,cis端为1 mol/L Bmim Cl、10 mmol/L Tris-HCl缓冲液(pH 5.5)的条件下,poly(dC)_(15)、poly(dC)_(20)、poly(dC)_(30)和poly(dC)_(50)均出现高抑制比的长阻断电流脉冲信号,长阻断事件的阻断深度达95%以上,持续时间达10^(-2)~10^(-1)s;同时,基线噪音峰峰值也降低约30%。对可能的机理进行了探讨。本研究结果表明,采用离子液体粘度梯度支持电解质体系可以有效调控ss DNA的迁移行为。Due to the difference in spatial configuration and charge of the bases in a DNA molecule,characteristic translocation current pulses through a single nanopore could be obtained.This could become the basis of DNA sequencing method.However,due to the fast translocation speed（sub-micro seconds）and the small current change（about p A）,it is still a challenge to obtain the accurate molecular substructure with present electronic techniques.In this work,in order to control the translocation behavior of ss DNA,two kinds of ionic liquids with high viscosity and conductivity were introduced to establish a viscosity gradient with theα-hemolysin single nanopore interface and the acidity of the solution was optimized.The trans chamber contained pure Bmim PF_6 and the cis chamber contained 1 mol/L Bmim Cl and 10 mmol/L Tris-HCl（pH 5.5）.Preliminary experiment results under this electrolyte configuration showed that poly（dC）_（15）,poly（dC）_（15）,poly（dC）_（30）and poly（dC）_（50）exhibited obvious long duration pulses with high current suppression ratio.The blocking depth reached more than 95%of long blocking events.The duration time of long blocking events prolonged to tens or hundreds of milliseconds.Meanwhile,the peak-peak of baseline noise was reduced by about 30%.

关 键 词：单个纳米孔 α-溶血素 单链DNA 离子液体 

分 类 号：Q523[生物学—生物化学]