A NONINVASIVE METHOD FOR THE TIGHT ANCHORING OF CELLS FOR SCANNING FORCE MICROSCOPY

Use of scanning force microscopy (SFM) for high resolution imaging of cell surfaces requires the cells to be tightly attached to substrates. Imaging of loosely adhered RBL-2H3 cells enabled determination of the cell size and investigation of larger structures and pseudopodia but failed in resolving more detail. Immobilization under non-invasive con ditions via flexible crosslinkers containing a hydrophobic anchoring g roup enhanced resolution enormously. The cells were tightly attached t o the substrates and were not removed by shear forces up to 80 nN as d etermined in a flow through apparatus. Morphological structures and dy namic processes on cell surfaces were observed as well as structural c hanges after cell stimulation upon ionomycin treatment. Molecular or a tomic resolution, however, was not attainable which is attributed to t he displacement of the flexible cell surface due to shear forces arisi ng from the scanning tip during contact mode. (C) 1997 Academic Press.