Surface activation of carbon film supports for biological electron microscopy

The effect of glow-discharging on naked carbon-filmed grids has been evaluated. The effect of different locations of the grids within a DC discharge, operated in the normal glow, was analyzed by applying various biological specimens to the grids. Two locations were found to give consistent results: (a) in Crookes dark space, particulate specimens, negatively stained, spread evenly--suggesting a new negative surface charge of the support; (b) below the anode, nucleic acids, selectively (positively) stained, appeared as well spread filaments, indicating a net positive surface charge.