A method for anchoring round shaped cells for atomic force microscope imaging

More and more researchers are interested in imaging living (Henderson, 1994) or fixed cells in their natural environment using the atomic force microscope (AFM). However, the AFM tip interacts strongly with the sample, and its z range freedom is limited to a few micrometers. This means that the cells to be imaged have to be strongly attached to the substrate, and imaging is restricted to cells having a flattened shape. Here we propose a simple and inexpensive solution to overcome these limitations. The method we propose is trapping living round shaped cells in a Millipore filter with a pore size comparable to the dimensions of the cell. The highest part of some of the blocked cells protrude through the holes of the filter and can this way be easily observed using the AFM without detachment.