The 1.4 nm Nanogold® particle is a gold compound: it is not just adsorbed to proteins, like colloidal gold, but covalently reacts at specific sites under mild buffer conditions.
The Nanogold® particle is covalently and specifically linked to a hinge thiol on Fab' or IgG. The conjugate therefore has excellent stability compared to colloidal gold-antibody preparations.
It is the first probe offered as a Fab' conjugate, which is the smallest gold-antibody probe commercially available. These substantially smaller probes reach more antigens and provide better labeling.
They can be viewed directly in TEM without silver enhancement or developed with silver to any appropriate size for enhanced visibility with other counterstains.
Whereas the stoichiometry of conventional gold probes particles to IgG molecules varies from 0.2 to 10, Nanogold® preparations contain close to one Nanogold® to one Fab' or IgG.
