Effects of pipette modulation and imaging distances on ion currents measured with Scanning Ion Conductance Microscopy (SICM)
Effects of pipette modulation and imaging distances on ion currents measured with Scanning Ion Conductance Microscopy (SICM)
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DOI：
10.1039/c0an00604a
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发表时间：
2011-01-01
期刊：
影响因子：
4.2
通讯作者：
Baker, Lane A.
中科院分区：
文献类型：
--
作者：
Chen, Chiao-Chen;Baker, Lane A.
局部电导变化可以通过扫描离子电导显微镜（SICM）测量离子电流大小来估计。对影响SICM测量离子电流成像质量和定量的因素进行了评价。具体来说，我们系统地研究了探针-样品分离和移液管调制对聚合物膜中孔隙在跨膜浓度梯度下成像电导变化的影响。利用距离调制（ac）反馈评价了探针-样品分离对离子电流图像的影响。采用非调制（直流）反馈获得的接近曲线也被记录下来，通过比较交流和直流反馈模式测量的离子电流来确定移液管产生的对流的相对影响。为了更好地解释所获得的结果，将其与基于膜中纳米孔圆盘几何形状的模型进行比较，并描述了实验的相关位置依赖参数。这些结果促进了我们目前对SICM电导测量的理解。
Local conductance variations can be estimated by measuring ion current magnitudes with scanning ion conductance microscopy (SICM). Factors which influence image quality and quantitation of ion currents measured with SICM have been evaluated. Specifically, effects of probe-sample separation and pipette modulation have been systematically studied for the case of imaging conductance variations at pores in a polymer membrane under transmembrane concentration gradients. The influence of probe-sample separation on ion current images was evaluated using distance-modulated (ac) feedback. Approach curves obtained using non-modulated (dc) feedback were also recorded to determine the relative influence of pipette-generated convection by comparison of ion currents measured with both ac and dc feedback modes. To better interpret results obtained, comparison to a model based on a disk-shaped geometry for nanopores in the membrane, as well as relevant position-dependent parameters of the experiment is described. These results advance our current understanding of conductance measurements with SICM.