Enhanced Single Molecule Mass Spectrometry via Charged Metallic Clusters

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• 作者：Christopher E. Angevine ; Amy E. Chavis ; Nuwan Kothalawala ; Amala Dass ; Joseph E. Reiner
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：November 18, 2014
• 年：2014
• 卷：86
• 期：22
• 页码：11077-11085
• 全文大小：446K
• ISSN：1520-6882

文摘

Nanopore sensing is a label-free method for characterizing water-soluble molecules. The ability to accurately identify and characterize an analyte depends on the residence time of the molecule within the pore. It is shown here that when a Au₂₅(SG)₁₈ metallic cluster is bound to an 伪-hemolysin (伪HL) nanopore, the mean residence time of polyethylene glycol (PEG) within the pore is increased by over 1 order of magnitude. This leads to an increase in the range of detectable PEG sizes and improves the peak resolution within the PEG-induced current blockade distribution. A model describing the relationship between the analyte residence time and the width of the peaks in the current blockade distribution is included. Finally, evidence is presented that shows the Coulombic interaction between the charged analyte and cluster plays an important role in the residence time enhancement, which suggests the cluster-based approach could be used to increase the residence time of a wide variety of charged analyte molecules.