title: Imaging of immunolabeled membrane receptors in uncoated SEM specimens.
abstract: Epidermal growth factor receptors (EGFR) were labeled with 10 nm immunogold and examined on uncoated specimens of A431 human epidermoid carcinoma cells. A field emission gun and a high-sensitivity YAG ring detector were used to demonstrate the affinity labeling simultaneously in the secondary-electron (SE) and backscattered-electron (BSE) modes with a low accelerating voltage (Vo). At Vo = 2 kV, the SE and BSE signals were too weak to identify all markers, while at Vo = 3-7 kV labeling was observed unambiguously in both the SE and BSE modes with smaller and higher working distances. Increasing the Vo to above 7 kV sometimes provokes instability of the specimens. A Vo of > or = 10 kV produces charging artifacts in the SE image, but permits a BSE image of the gold markers providing additional topographic information. In conclusion, immunogold labeling can be used with good results for uncoated specimens.
authors.affiliation: GSF Research Center for Environment and Health GmbH, Institute for Pathology, Munich, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Heinzmann
authors.forename: A
authors.initials: A
authors.lastname: Reninger
authors.forename: R
authors.initials: R
authors.lastname: Autrata
authors.forename: H
authors.initials: H
authors.lastname: Höfler
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology; D002462:Cell Membrane / Q000648:ultrastructure; D066246:ErbB Receptors / Q000648:ultrastructure*; D006801:Humans; D007150:Immunohistochemistry; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D016253:Microscopy, Immunoelectron / Q000379:methods; D014407:Tumor Cells, Cultured
chemical_list: D066246:ErbB Receptors