Gold Conjugate Technical Information
The MSDS for EM grade Gold Conjugates can be downloaded from here
BBI Gold Conjugates are made to the highest possible specification and will give the best possible results in all applications when correctly used. This booklet is designed to help achieve the best results by giving attention to specimum preparation, choice of gold conjugate and incubation conditions with different specimum types. It is not comprehensive. Many books and articles have been written describing the extensive techiniques of immunogold labelling. This booklet will, however, endeavour to describe the fundamental factors which influence the result that can be obtained, suggest a number of commonly used protocols, and point to to solutions to common problems. Read more here
The usefulness of streptavidin: gold conjugates is due to the high affinity of streptavidin for biotin (dissociation constant of 10"19M). Streptavidin has four binding sites for biotin but fewer than four molecules will actually bind. Biotinylation of a primary anntibody or nucleic acid probe is a mild process where biotin is covalently linked to the protein or probe. The streptavidin conjugate then binds to the biotin during incubation and provides a visible gold label that may be directly viewed in the EM or observed in the LM (or EM) after silver enhancement. Read more here
BBInternational Cationic Gold allows highly sensitive and discrete microscopical studies of anionic sites in and on cells and tissues. A simple one step incubation of sections with the diluted gold conjugate at the correct pH reveals subcellular sites having net negative charge. The charge distribution may be examined with clear definition at a range of magnifications in the electron microscope by employing cationic gold of different sizes or by enhancing gold particles in situ with the BBI silver enhancing kit for light microscopy a single size is used and subsequently silver enhanced.
Most cells of eukaryotic origin have a net negative surface charge from anionic plasma membrane components. This charge is thought to be important in the movement of various soluble macromolecules across cell walls. The role of this surface charge in cellular behavior through interaction with neighbouring cells or with the intracellular matrix can now be studies microscopically with high definition by a simple one step procedure. A further advantage of cationic gold is the possibility of performing labeling studies under various physiological conditions of pH and ionic strength. For further information read here