The use of electron energy loss spectroscopy for studying membrane architecture: a preliminary report

Some initial measurements of interest with respect to the use of energy loss spectroscopy (ELS) in the electron microscope are reported. We have obtained energy loss spectra in the region less than 15 eV energy loss for three components of biological components; lecithin, cholesterol and spectrin. Some indications of the effect of electron beam damage on the cholesterol spectrum are shown. In addition, energy loss pictures of erythrocyte membrane fragments are demonstrated for various energy losses less than 40 eV (taken with 0.75 eV width window) and it is shown that an individual ferritin molecule can be identified on the basis of its iron MII-III excitation line. From the results of the preliminary data we have discussed the possibilities of ELS for studies of biological membranes.