This may or may not be what you're looking for, and I wish I could remeber the
investigator's name (she was at a Swiss federal academic institution,
presented a poster at a conference in '94...if this _is_ of interest I can dig
up the conference proceedings.)

The technique was secondary electron x-ray spectroscopy, with the strong
advantage of unambiguous elemental identification with moderate lateral
resolution (submicron, not low nanometer).  It was used to show Al deposits in
fetal chick cells.

Ely Rabani
CTO
BioSystemaTec