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Although the dynamics of cell membranes and associated structures is vital for cell function, little is known due to lack of suitable methods. We found, using scanning ion conductance microscopy, that microvilli, membrane projections supported by internal actin bundles, undergo a life cycle: fast height-dependent growth, relatively short steady state, and slow height-independent retraction. The microvilli can aggregate into relatively stable structures where the steady state is extended. We suggest that the intrinsic dynamics of microvilli, combined with their ability to make stable structures, allows them to act as elementary "building blocks" for the assembly of specialized structures on the cell surface. [ABSTRACT FROM AUTHOR]

We describe hopping mode scanning ion conductance microscopy that allows noncontact imaging of the complex three-dimensional surfaces of live cells with resolution better than 20 nm. We tested the effectiveness of this technique by imaging networks of cultured rat hippocampal neurons and mechanosensory stereocilia of mouse cochlear hair cells. The technique allowed examination of nanoscale phenomena on the surface of live cells under physiological conditions. [ABSTRACT FROM AUTHOR]

A correction to the article "Nanoscale Live-Cell Imaging Using Hopping Probe Ion Conductance Microscopy" that was published in the March 1, 2009 issue is presented.

Background: Continuous high spatial resolution observations of living A6 cells would greatly aid the elucidation of the relationship between structure and function and facilitate the study of major physiological processes such as the mechanism of action of aldosterone. Unfortunately, observing the micro-structural and functional changes in the membrane of living cells is still a formidable challenge for a microscopist. Method: Scanning ion conductance microscopy (SICM), which uses a glass nanopipette as a sensitive probe, has been shown to be suitable for imaging non-conducting surfaces bathed in electrolytes. A specialized version of this microscopy has been developed by our group and has been applied to image live cells at high-resolution for the first time. This method can also be used in conjunction with patch clamping to study both anatomy and function and identify ion channels in single cells. Results: This new microscopy provides high-resolution images of living renal cells which are comparable with those obtained by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Continuous 24 h observations under normal physiological conditions showed how A6 kidney epithelial cells changed their height, volume, and reshaped their borders. The changes in cell area correlated with the density of microvilli on the surface. Surface microvilli density ranged from 0.5 μm-2 for extended cells to 2.5 μm2 for shrunk cells. Patch clamping of individual cells enabled anatomy and function to be correlated. Conclusions: Scanning ion conductance microscopy provides unique information about living cells that helps to understand cellular function. It has the potential to become a powerful tool for research on living renal cells. [Copyright &y& Elsevier]