Simple to use-- incredible results. Precise, permanent labeling with Nanogold®
5 nm Sulfo-NHS-Nanogold® is a highly monodisperse, highly water-soluble, stable, and biocompatible 5 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).
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 5 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.
Schematic showing reaction of 5 nm Sulfo-NHS-Nanogold® with an amino-functionalized molecule.
Use our unique Nanogold® labeling reagents just as you would use fluorescent labeling reagents.
Labeling with 5 nm Sulfo-NHS-Nanogold®, like the smaller 1.4 nm Sulfo-NHS-Nanogold®, is straightforward: Simply mix reconstituted 5 nm Sulfo-NHS-Nanogold® with the target molecule for one hour at room temperature or 16 h in the refrigerator.
Once reaction is complete, conjugates may be chromatographically separated by gel filtration. Alternatively, labeled proteins may be isolated by ammonium sulfate precipitation, and oligonucleotides by ethanol precipitation or gel electrophoresis. 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.
5 nm Nanogold® Labeling Reagents
The precision and versatility of Nanogold®, now in a larger 5 nm size
Like our smaller 1.4 nm Nanogold® reagents, it covalently reacts at specific sites under mild buffer conditions. This gives a well defined product that can be purified chromatographically or by ammonium sulfate precipitation.
Unlike conventional colloidal gold, 5 nm Nanogold® does not require any additional macromolecules for stabilization. Conjugate probes are smaller than colloidal gold probes and achieve higher resolution, more precise and more nearly quantitative labeling.
Make any molecule a gold probe
Nanogold® brings the versatility of fluorescent conjugation to gold labeling. Now you have a choice of sizes for Nanogold®: 0.8, 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
Unconjugated 5 nm Nanogold®, showing monodisperse, highly regular, spherically symmetrical 5 nm gold core and uniform, thin and consistent ligand coating. This ensures a highly regular particle size, smaller probe size, and reliable, reproducible labeling and EM results.
Easily enhanced for electron microscopy, light microscopy, cryo-EM, blots…
Try our precision nanoparticle developers for easily controlled development with low background!
Features and Advantages
- Stable, soluble and biocompatible: Designer coating gives solubility and biocompatibility for in vivo use. No residual charge means minimal non-specific binding.
- Highly monodisperse. Size variation less than 15% for 5 nm gold. 1.4, 5 and 12 nm Nanogold® enable up to triple labeling with non-overlapping sizes
- Molecular precision: 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: smaller probes penetrate better and label more densely.
- Easily enhanced. Silver or gold enhancement enlarges while retaining monodispersity – or affords super-sensitive detection for blots and optical systems.
- Pick the optimum size: smaller for high resolution, molecular labeling, larger for visualization on a cellular scale.
Although larger than our 1.4 nm Nanogold®, our new 5 nm Nanogold® is still relatively small in size, and highly uniform. Because it does not require additional proteins for stabilization, 5 nm Nanogold® conjugates are smaller than most conjugates prepared with conventional colloidal gold and uniform in overall size, giving them faster and more consistent penetration into specimens.
If larger particle sizes are needed, 5 nm Nanogold® may easily be enhanced with GoldEnhance™ gold enhancement reagents, or our HQ Silver™ or LI Silver™ silver enhancement reagents: Depending on the reagents used, a brief exposure (1 – 4 minutes) produce highly visible grains 10-20 nm in size for electron microscope identification, 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.