Investigation of hydration structures and surface charges on biomolecules by three-dimensional force mapping

2015 Fiscal Year Final Research Report

• Project/Area Number: 25286057
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Thin film/Surface and interfacial physical properties
• Research Institution: Kyoto University
• Principal Investigator: Kobayahi Kei 京都大学, 白眉センター, 特定准教授 (40335211)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 走査プローブ顕微鏡 / 原子間力顕微鏡

Outline of Final Research Achievements

We recently developed frequency-modulation atomic force microscopy (FM-AFM) in liquids and made it possible to explore solid-liquid interface properties such as the hydration structures and surface charges with a nanometer-scale resolution. In this project, we employed FM-AFM to study the hydration structures and surface charges of biomolecules such as DNA by using two-dimensional (2D) and three-dimensional (3D) force mapping techniques. We obtained a 3D frequency shift map on a plasmid DNA molecule in a buffer solution with 50 mM nickel chloride. The map showed complicated contrast patterns with a sub-nanometer-scale resolution, which reflect the hydration structures around the DNA molecule. We also obtained a 3D frequency shift map on a lambda DNA molecule adsorbed on a poly-L-lysine (PL) layer on a mica substrate in potassium chloride solutions. By analyzing the frequency shift versus distance curves, we estimated the charge density of the labmda DNA molecule and the PL layer.

Free Research Field

工学