Universal Biologicals Cambridge
Reagents, Assays and Tools for Life Science Research
http://www.nanoprobes.com/
Gold Labeling Reagents and Immunoprobes
Nanogold® is a better gold label. The 1.4nm 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. This gives a well defined product that can be purified chromatographically.
Nanogold® brings the versatility of fluorescent conjugation to gold labeling. It may be used to label any molecule with a suitable reactive group: oligonucleotides, lipids, peptides, proteins, enzyme inhibitors and others, unlike colloidal gold which may be adsorbed only to antibodies and a limited range of proteins and peptides. Nanogold® is small and highly uniform in size, in sharp contrast to small colloidal gold preparations (most commonly used ‘1nm’ gold actually range from 1 to 3nm ). Nanogold® is available both as a labelling reagent for labeling your own biomolecules in a range of antibody IgG, Fab’ and streptavidin conjugates.
Although smaller than most other EM probes, it can easily be enhanced with silver (LI Silver or HQ Silver) by brief exposure (1-5 mins) to produce highly visible grains 2-20nm in size (depending on development time). Further development (8-25 mins) gives a black signal easily seen in the light microscope and on immunoblots, polyacrylamide gels and Western blots.
Features of Nanogold®
Features of Nanogold® Conjugates
Nanogold Conjugates contain a Nanogold particle which 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.
Nanogold® Conjugates
Histidine-tagged Protein Detection
Features of FluoroNanogold™
FluoroNanogold is a new immunoprobe which contains both a fluorescent label and the Nanogold cluster.
Fluorescein FluoroNanogold™
Alexa Fluor® 488 - FluoroNanogold™
Alex Fluor® 594 - FluoroNanogold™
Gold Lipids are designed to study membranes designed to study membranes by incorporation into the liquid phase, or to be used to gold-label miscelles and vesicles so they may be identified and visualised.
With Silver Enhancers, Gold particles such as Nanogold® may be enlarged up to 30 – 100nm in size resulting in greatly enhanced visibility in EM and light microscopy.
GoldEnhance is similar to silver enhancement, but deposits gold around the initial gold particle giving a higher density of enlarged particles for clearer imaging.
EnzMetTM uses a targeted enzymatic probe with a novel metallographic substrate to provide a quantum leap in staining clarity over conventional chromogenic and fluorescent substrates.
Negative stains are reagents which contain heavy atoms and do not crystallize upon drying. They are used to visualise the edges of protein complexes, macromolecules and cells in suspension.
Undecagold (Au11) is smaller than Nanogold®, with a core of 11 gold atoms only 0.8nm in diameter. It is ideal for ultra-high resolution EM work such as scanning transmission electron microscopy, or for resolving elements of large structures by TEM in conjunction with image processing. Undecagold has been used to see the biotin binding siteson avidin to 1nm resolution by electron microscopy. It is prepared in a form with one reactive arm for cross-linking to a specific site on a target molecule, and is available with different reactivities for labeling different sites.