T. Takizawa et Jm. Robinson, FluoroNanogold is a bifunctional immunoprobe for correlative fluorescence and electron microscopy, J HIST CYTO, 48(4), 2000, pp. 481-485
We applied a fluorescent ultrasmall immunogold probe, FluoroNanogold (FNG),
to immunocytochemistry on ultrathin cryosections. FNG has the properties o
f both a fluorescent dye-conjugated antibody for fluorescence microscopy an
d a gold particle-conjugated antibody for electron microscopy. Therefore, t
his bifunctional immunoprobe permits correlative microscopic observation of
the same cell profiles labeled in a single labeling procedure by these two
imaging methods. We demonstrate the utility of FNG as a secondary antibody
for immunocytochemical labeling of myeloperoxidase (a marker protein for a
zurophilic granules) in ultrathin cryosectioned human neutrophils. Its dete
ction requires high spatial resolution because neutrophils contain many cyt
oplasmic granules. There was a one-to-one relationship between fluorescent
structures labeled with FNG and organelle profiles labeled with the same si
lver-enhanced FNG in ultrathin cryosections. Use of FNG immunocytochemistry
on ultrathin cryosections is an ideal methodology for high-resolution corr
elative fluorescence and electron microscopy and can provide unique informa
tion that may be difficult to obtain with a single imaging regimen.