A 1.4-nm gold cluster covalently attached to antibodies improves immunolabeling

• Published in: The journal of histochemistry and cytochemistry Vol. 40; no. 2; pp. 177 - 184
• Main Authors: Hainfeld, JF, Furuya, FR
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA Histochemical Soc 01.02.1992; SAGE Publications; Histochemical Society
• Subjects: Animals; Biological and medical sciences; Erythrocytes - immunology; Ferritins - analysis; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Gold; HeLa Cells; Humans; Immunoglobulin Fab Fragments; Immunoglobulin G; Immunohistochemistry - methods; Microscopy, Electron, Scanning - methods; Microscopy, Immunoelectron - methods; Molecular immunology; Rabbits - immunology; Techniques; IgG; Immunoblotting assay; Immunogold labelling; Fab-Fragment; Antigenic determinant; Electron microscopy
• ISSN: 0022-1554; 1551-5044
• DOI: 10.1177/40.2.1552162

A large gold cluster (Au1.4nm) was covalently coupled to IgG and Fab' fragments. Its gold core is 1.4 nm in diameter and the Fab'-Au1.4nm immunoconjugate is the smallest gold immunoprobe that can be seen directly in the conventional electron microscope. It is useful in high-resolution immunolabeling, providing a resolution of 7.0 nm. The cluster's visibility can be enhanced with silver development for use in EM or light microscopy for histological purposes, or to detect less than or equal to 0.2 pg of antigen in immunoblots. By using a gold compound with covalent attachment, a number of advantages over colloidal gold probes are realized, including better resolution, stability, uniformity, sensitivity, and complete absence of aggregation; its small size should also improve penetration and more quantitative labeling of antigenic sites.