Motile behavior and topography of whole and enucleate mammalian cells on modified substrates

Most mammalian cells when placed in tissue culture are capable of autonomous motility, but the mechanisms and properties of this locomotion are not well understood. To test the behavior of cultured cells on substrata of variable composition, we used ordinary electron microscope grids as stencils while evaporating gold wire onto glass coverslips coated with cellulose acetate. Whole CHO or L-929 cells growing in monolayer culture were then trypsinized and plated on these prepared coverslips and fixed at various intervals for observation in the scanning electron microscope. In all cases studied, the whole cells were observed to accumulate on the gold areas in preference to the cellulose acetate. In addition, by centrifuging cells in the presence of cytochalasin B (CB), we obtained populations of enucleated cells (cytoplasts) which were then replated on these coverslips. Even though replated cytoplasts are capable of limited motility, they were not observed to preferentially select substrates as did intact cells.