12 nm Sulfo-NHS-Nanogold® is a highly monodisperse, highly water-soluble, stable, and biocompatible 12 nm gold nanoparticle, with a hydrophilic coating, modified with Sulfo-NHS groups that react with aliphatic amines under mild conditions (pH 7.5 to 8.2).
Use our unique Nanogold® labeling reagents just as you would use fluorescent labeling reagents.
Labeling with 12 nm Sulfo-NHS-Nanogold®, like the smaller 5 nm Sulfo-NHS-Nanogold®, is straightforward: Simply mix reconstituted 12 nm Sulfo-NHS-Nanogold® with the target molecule for one hour at room temperature or 16 h in the refrigerator.
Once reaction is complete, labeled proteins may be isolated by ammonium sulfate precipitation, and oligonucleotides by ethanol precipitation or gel electrophoresis. Alternatively, conjugates may be chromatographically separated by gel filtration; ion exchange chromatography or hydrophobic interaction chromatography may also be useful.
The sulfo-NHS group specifically reacts with an amine under mild conditions to produce a stable, covalent amide bond.
Schematic showing reaction of 12 nm Sulfo-NHS-Nanogold® with an amino-functionalized molecule.
Selectively label any molecule with an accessible amino-group
- Antibody IgG and IgM: label at an N-terminal amine or lysine residue – no need for reduction or other pretreatment. Conserve rare or low abundance antibodies.
- Antibody Fab or ScFv fragments: label small antibody fragments without unique thiol sites.
- Proteins and peptides: Label an N-terminal amines or lysine residues. Disulfide bridges remain intact: preserve tertiary and quaternary structures.
- DNA, RNA and PNA: Use an amino-modified phosphoramidite or lysine during synthesis to put an amine right where you want the gold. Amino- modifications may be introduced anywhere – you are not restricted to 3′ or 5′ terminal labeling.
- Nanostructured materials: label an amino-functionalized building block, then assemble to make programmed gold nanoparticle arrays. Or program amino- labeling sites into self-assembled materials and add the gold afterwards.
- Small molecules: Decorate 12 nm Nanogold® with small molecules such as hormones, inhibitors, or signalling molecules, then localize binding sites with molecular precision.*
- * 5 nm Sulfo-NHS Nanogold® is polyfunctional, so labeling reactions need to be planned to avoid cross-linking and control the ratio of Nanogold® to conjugate biomolecule. See the product information and instructions for more information and suggestions.
12 nm Nanogold® Labeling Reagents
Precise, permanent Nanogold® labeling reagents – Now in a larger size!
12 nm Nanogold® brings the power and versatility of Nanogold® in a even larger and more readily visualized 12 nm size. Like our smaller 5 nm and 1.4 nm Nanogold® reagents, it covalently reacts at specific sites under mild buffer conditions to give a well-defined product that may be purified chromatographically or by ammonium sulfate precipitation.
Unlike conventional colloidal gold, 12 nm Nanogold® does not require any additional macromolecules for stabilization. Conjugate probes are often smaller than colloidal gold probes and can achieve higher resolution because they can be prepares using smaller targeting agents, giving more precise and more nearly quantitative labeling.
Make any molecule a gold probe!
Unconjugated 12 nm Nanogold®, showing monodisperse, highly regular, spherically symmetrical 12 nm gold core and uniform, consistent ligand coating. This ensures a highly regular particle size and reliable, reproducible labeling and EM results.
Nanogold® brings the versatility of fluorescent conjugation to gold labeling.
Now you have a choice of sizes for Nanogold®: 1.4, 5 or 12 nm, enabling multiple labeling for electron microscopy without silver or gold enhancement!
- Antibodies
- Proteins
- Peptides
- Oligonucleotides and nucleosides: DNA, RNA and PNA
- Nanostructured materials
- Hormones
- Polymers
- Surfaces
Features and Advantages
- Stable, soluble and biocompatible. Designer coating gives solubility and biocompatibility so conjugates and probes may be used in vivo.
- Low background. No residual charge: minimal non-specific binding.
- Highly monodisperse. Size variation less than 10% for 12 nm. 1.4, 5 and 12 nm Nanogold enable double or even triple labeling with non-overlapping sizes
- Molecular precision. Use smaller targeting agents to make smaller primary probes that get the gold closer to the target.
- Site-specific conjugation enables programmed incorporation into nanostructured materials or components of self-assembling systems.
- No need for additional proteins or polymers: preparation is straightforward with no need for salt titration.
- Pick the optimum size: smaller for high resolution, molecular labeling, larger for visualization on a cellular scale.
- Easily enhanced. Enlarge with silver or gold enhancement and retain higher monodispersity – or achieve super-sensitive detection for blots and optical detection systems. If larger particle sizes are needed, 12 nm Nanogold® may easily be enhanced with:
Depending on the reagents used, a brief exposure (1 – 4 minutes) produces highly visible grains 20-30 nm in size for wide-field electron microscope visualization, while longer development times produce black signals, readily differentiated from organic chromogens, that are easily seen in the light microscope and on immunoblots, gels and Western blots.