Abstract
An influx of calcium ions into a living cell occurs when the cell is deformed mechanically by compressing, indenting or stretching. The calcium ions are taken up through mechanosensitive channels sensing deforming signals. The calcium ion is a key trigger for the reformation of cytoskeletal structure. Indentation of a capillary to a cell during microinjection causes influx of calcium ions, as does a typical AFM tip. A nanoneedle, which is a sharpened needle shaped AFM tip of 200 nm in diameter does not cause any influx of calcium ions when it is inserted into a cell. The mechanical stress from the nanoneedle insertion is negligible and its invasiveness is low.
