Kelvin probe force microscopy in application to biomolecular films: Frequency modulation, amplitude modulation, and lift mode
Kelvin probe force microscopy in application to biomolecular films: Frequency modulation, amplitude modulation, and lift mode
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DOI：
10.1016/j.ultramic.2010.02.036
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发表时间：
2010-05-01
期刊：
影响因子：
2.2
通讯作者：
Leonenko, Zoya
中科院分区：
文献类型：
--
作者：
Moores, Brad;Hane, Francis;Leonenko, Zoya
开尔文探针力显微镜（KPFM）是一种强大的技术，可用于观察金属功函数的差异以及有机薄膜横向表面电势分布。我们之前已经表明，当应用于真空中的金属和无机界面时，调频 - 开尔文探针力显微镜在灵敏度和分辨率方面都具有显著优势。为了研究具有生物学相关性的样品，需要在环境条件下具有高分辨率、高灵敏度和良好性能。在这项工作中，我们比较了调频（FM - KPFM）、调幅（AM - KPFM）和提升模式KPFM对复杂生物分子膜局部表面电势成像的分辨率，并证明了FM - KPFM模式在生物应用中具有卓越的分辨率。该方法的优势在肺表面活性物质膜上得到了体现，在环境空气中显示出纳米级的空间分辨率和毫伏级的电势灵敏度。在这种分辨率水平下，该方法能够以其他KPFM模式无法做到的方式，为复杂生物系统的分子排列和功能提供关键的见解。基于对局部表面电势变化的观察，我们发现过量的胆固醇会产生纳米尺寸的静电畴并改变电场。（C）2010爱思唯尔有限公司。保留所有权利。
Kelvin probe force microscopy (KPFM) is a powerful technique to visualize the differences of work function in metals and lateral surface potential distribution in thin organic films. Earlier we have shown that frequency modulated-Kelvin probe force microscopy has significant advantages in both sensitivity and resolution when applied to metal and inorganic interfaces in vacuum. High resolution, high sensitivity, and performance in ambient conditions are required in order to study biologically relevant samples. In this work we compared the resolution of frequency modulation (FM-KPFM), amplitude modulation (AM-KPFM), and lift modes KPFM for imaging the local electrical surface potential of complex biomolecular films and demonstrated that FM-KPFM mode has superior resolution for biological applications. The power of the method was illustrated on pulmonary surfactant films, revealing nm spatial resolution and mV potential sensitivity in ambient air. At this level of resolution this method can provide critical insight into the molecular arrangement and function of complex biosystems in a way that other KPFM modes cannot do. Based on the observed changes in the local surface potential we discovered that excess cholesterol produces nm size electrostatic domains and change the electric fields. (C) 2010 Elsevier B.V. All rights reserved.