4 nm Dodecanethiol-Stabilized Gold Nanospheres
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Which Surface Should I Choose?
at pH 7
Certificate of Analysis Examples
Please note that these are representative Certificates of Analyses (CoAs) provided as examples for this product. We provide a unique batch-specific CoA with each product during shipment; only the CoA that arrives with your product should be referred to for actual characterization and measurement data. If you would like an electronic copy of the CoA for the product you received or the material(s) we currently have in stock, please contact us.
|Product Line||Surface||Example Certificate of Analysis||Product #||Price|
|D NanoXact, Dried||Dodecanethiol (Nonpolar Solvent Compatible)||AUDD4-1MG||$120+|
|D NanoXact, Dried||Dodecanethiol (Nonpolar Solvent Compatible)||AUDD4-5MG||$475+|
|D NanoXact, Dried||Dodecanethiol (Nonpolar Solvent Compatible)||AUDD4-25MG||$1,375+|
|D NanoXact, Dried||Dodecanethiol (Nonpolar Solvent Compatible)||AUDD4-50MG||$2,150+|
Gold Nanoparticle Applications
Gold nanopaticles are readily conjugated to antibodies and other proteins due to the affinity of sulfhydyl (-SH) groups for the gold surface, and gold-biomolecule conjugates have been widely incorporated into diagnostic applications, where their bright red color is used in home and point-of-care tests such as lateral flow assays.
Gold nanomaterials can be conjugated to biomolecules to specifically target cancer cells, and used for photothermal cancer therapy, where their tunable optical properties cause them to convert laser light into heat and selectively kill cancerous cells.
Gold nanoparticles have unique optical properties because they support surface plasmons. At specific wavelengths of light the surface plasmons are driven into resonance and strongly absorb or scatter incident light. This effect is so strong that it allows for individual nanoparticles as small as 30 nm in diameter to be imaged using a conventional dark field microscope. This strong coupling of metal nanostructures with light is the basis for the new field of plasmonics. Applications of plasmonic gold nanoparticles include biomedical labels, sensors, and detectors. The gold plasmon resonance is also the basis for enhanced spectroscopy techniques such as Surface Enhanced Raman Spectroscopy (SERS) and Surface Enhanced Fluoressence Spectroscopy which can be used to detect analytes with ultrahigh sensitivity.
Ultra Uniform Gold Nanospheres
Our standard Au nanospheres have a variety of useful surface chemistries and narrow size distributions (CV < 15%), appropriate for a variety of applications ranging from lateral flow assays to optical coatings. Some applications, however, such as multiplexed dark field labeling or standards for nanoparticle size and shape, require even tighter tolerances on shape and size dispersity. For these applications, nanoComposix has successfully manufactured ultra-uniform, monodisperse gold nanospheres with sizes tunable from 10 nm up to 200 nm. As shown below, these gold nanoparticles have a nearly perfect spherical shape, smooth surfaces, and impressively narrow size distributions (CV < 6%, and for many sizes CV < 4%).
Optical and Scattering Properties
Due to their high uniformity in size and shape, these Au nanospheres scatter a single color of light under dark field microscope imaging (shown below). The high purity of their light scattering signatures makes these nanospheres perfect scattering labels for imaging and building blocks for plasmonic nanostructures and devices.
The gold nanospheres are stabilized with citrate in an aqueous solution. With their stable, easily displaceable surface chemistry, the gold nanospheres can be readily functionalized with a wide variety of molecules, including polymers and small molecules with desired functional groups, inorganic coatings such as silica, and biomolecules including DNA and antibodies for your application.
To redisperse the particles, we recommend adding an appropriate solvent from the Table below to the dried powder and vortexing for 30 seconds. After redispersion, samples should be stored at 4°C and away from light, as described in our Storage and Handling instructions.
|Solvent Refractive Index, n||Nanopowder Solubility|
Effect of Solvent on Nanoparticle Optical Properties
UV-visible spectroscopy can be used to detect the presence of aggregation or changes in particle size; such effects are readily observed in the absorption spectrum as a change in the width of the plasmon peak and/or the appearance of a secondary peak that is red-shifted from the plasmon peak. Samples of a hexane dispersion of 4 nm-diameter dodecanethiol-coated Ag nanoparticles were dried and re-suspended in a variety of organic solvents. The absorption spectrum of the resuspended sample is compared with that of the original hexane dispersion in the figures below.
Small changes in the UV-visible absorption spectra of the redispersed samples are seen when compared with the original hexane dispersion. The shifting and broadening of the the spectra are typical of those seen during solvent transfer due to a change in the refractive index of the solvent, and are not due to changes in particle size or agglomeration.