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 12 nm Nanogold® Labeling Reagents: the power of Nanogold® in a 12 nm Size
Updated: June 13, 2025
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Product information and resources
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5 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.
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.
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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®: 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
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- Nanostructured materials
- Hormones
- Polymers
- Surfaces
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Features and Advantages
- Stable, soluble and biocompatible: Designer coating gives solubility and biocompatibility so conjugates and probes may be used in vivo.
- No residual charge: minimal non-specific binding.
- Highly monodisperse. Size variation less than 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.
- Easily enhanced. Enlarge with silver or gold enhancement and retain higher monodispersity - or achieve super-sensitive detection for blots and optical detection systems.
- Pick the optimum size: smaller for high resolution, molecular labeling, larger for visualization on a cellular scale.
If larger particle sizes are needed, 12 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) 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.
 12 nm Sulfo-NHS-Nanogold®
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Schematic showing reaction of 12 nm Sulfo-NHS-Nanogold® with an amino-functionalized molecule.
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.
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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.
Product information
12 nm Maleimido Nanogold®
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Schematic showing reaction of 12 nm Maleimido Nanogold® with a thiol-functionalized molecule.
12 nm Maleimido Nanogold® is a highly monodisperse, highly water-soluble, stable, and biocompatible 12 nm gold nanoparticle, with a hydrophilic coating, modified with maleimide groups that react with thiols (sulfhydryls) under mild conditions (pH 6.0 to 7.0).
Use our unique Nanogold® labeling reagents just as you would use fluorescent labeling reagents. Labeling with 12 nm Maleimido Nanogold®, like the smaller 5 nm Maleimido Nanogold®, is straightforward: Simply mix reconstituted 12 nm Maleimido 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 maleimide group specifically reacts with a thiol under mild conditions to produce a stable, covalent thioether bond.
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Selectively label any molecule with an accessible thiol group:
- Antibody IgG and IgM: label at a hinge thiol, remote from the binding site - preserve affinity.
- Antibody Fab' fragments: attach the 5 nm Nanogold® at the hinge thiol at the opposite end to the binding site - preserve maximum native binding affinity.
- Proteins and peptides: Label selectively at a unique thiol site, or incorporate a unique Cys residue during peptide synthesis at the site you wish to label.
- DNA, RNA and PNA: Use a thiol-modified phosphoramidite or cysteine during synthesis to put a thiol right where you want the gold - or modify enzymatically in situ to place the gold at the modification site.
- Nanostructured materials: label a building block, then assemble for a programmed gold nanoparticle array, or program specific labeling sites into a nanostructure 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.*
* 12 nm Maleimido 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.
Product information
12 nm Amino Nanogold®
Selectively label unique sugar or activated carboxyl sites
Positively ionizing amino- groups enable charge-based staining or labeling of negatively charged targets
- Carboxyl labeling: Label at carboxylic acid residues by converting the carboxylic acid to an activated form for reaction with 12 nm Amino Nanogold®.
- Carbohydrate labeling: use periodate or other mild, selective oxidants to oxidize carbohydrate sugars to aldehydes, then react with 12 nm Amino Nanogold® and reduce the resulting imides to give stable, amine-linked conjugates. See our Application note on RNA labeling for details.
- Protein labeling: activate 12 nm Amino Nanogold® using amine-reactive cross-linkers cross-link to a variety of other functional groupsor targets.
- Charge-based labeling: Under slightly acidic conditions, 12 nm Amino Nanogold® protonates and assumes a positive charge: use to label negatively ionizing regions in proteins or organelles.
- Make DNA nanowires: like the smaller 1.4 nm Positively Charged Nanogold®, 12 nm Amino Nanogold® can bind to the negatively charged groups in the DNA backbone; see our Microscopy & Microanlaysis 2001 paper for details. silver or gold enhance to make conductive nanowires.
* 12 nm Amino 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 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).
Use our unique Nanogold® labeling reagents just as you would use fluorescent labeling reagents. Labeling with 12 nm Amino-Nanogold®, like the smaller 1.4 nm Amino-Nanogold®, is straightforward: reconstitute the 5 nm Amino Nanogold®, activate with the appropriate cross-linker, then incubate with the target molecule under suitable conditions.
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.
Product information
12 nm Non-Functional Nanogold®
12 nm Non-Functional Nanogold® is a highly soluble, non-ionizing, regular 12 nm coated gold nanoparticle.
- Use as a fiducial marker: 12 nm Non-Functional Nanogold® is highly regular, stable and biocompatible. Use as a small fiducial marker for aligning high-resolution tilt sections or for electron tomography.
- Use for sizing: 12 nm Non-Functional Nanogold® is highly regular in size: the gold nanoparticle is 12 nm in diameter, and the overall diameter, including the shell, is close to 24 nm. Use to determine size limits for crossing cellular junctions or for sizing pores.
- Use for mapping: 12 nm Non-Functional Nanogold® is highly water-soluble, stable, and non-ionizing. It has minimal affinity for proteins or cellular components, and therefore may be used to map contiguous internal spaces, such as neurons or vacuoles, or connectivity.
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Product information
Custom 12 nm Nanogold® Conjugates and Labeling
Nanoprobes can perform custom conjugation using any of our Nanogold®, undecagold or colloidal gold labels with primary antibodies, proteins, peptides, DNA, RNA or PNA, small molecules, nanomaterials components, surfaces or other materials. Custom FluoroNanogold™ labeling is available for antibodies or larger proteins. This includes the purification and characterization of conjugates. Call 877-447-6266 (US toll-free number) or (631) 205-9490, use our custom synthesis quotation form, or e-mail us at tech@nanoprobes.com to discuss your project and obtain a quote.
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