UNCONVENTIONAL IMMUNE DOUBLE-LABELING BY ENERGY-FILTERED TRANSMISSIONELECTRON-MICROSCOPY

A new method of immune double labelling of biological specimens with a very high spatial resolution is presented. The advantage over convent ional techniques is the possibility of using two very small labels lea ding to higher labelling efficiency, better penetration into the speci men and reduced steric hindrance between labels at closely spaced site s, The two labels are distinguished by their electron energy loss spec tra using principal component analysis and then identified by comparis on with an external standard using discriminant function analysis, The method is tested on samples of insect flight muscle labelled with 8 n m colloidal gold and silver and the statistical reliability of the cla ssification is assessed. Extensions of the method are suggested and it s potential for biological research is discussed.