Metal nanoparticles support localized surface plasmon resonances, collective oscillations of conduction electrons that strongly couple to light at specific wavelengths and produce extremely high electromagnetic fields near the nanoparticle surface. Surface Enhanced Raman Scattering (SERS) can increase the Raman signal by more than 6 orders of magnitude. Fluorescent molecules near the metal particle surface can also be enhanced and can be protected from photobleaching in an effect known as Surface Enhanced Fluorescence (SEF).
For SERS applications, plasmonic nanoparticles with areas of high curvature produce the largest field enhancements (e.g. rod, cubic, pyramidal, or plate geometries). Controlled aggregation of particles into doublets or triplets also produce high enhancements, especially when the SERS molecule can be trapped in the junction between the particles. For SEF, the fluorescent molecules also need to be in high localized field but if the fluorescent molecule is too close to the metal surface, its emission can be “quenched”. Thus, SEF particles are engineered to position the fluorescent molecule a few nanometers away from the particle surface.
NanoComposix has been developing SERS and SEFS particles for more than 10 years. Plasmonic nanoparticles with resonance wavelengths from 400 nm to 1000 nm that have ultra-clean bare surfaces ideal for SERS applications are available as stock product and other size and wavelength variants are available as custom orders. For SEFS, there is a requirement that the molecules be separated from the metal surface by a fixed amount (typically 5 to 10 nm). Silica shelled plasmonic nanoparticles are often used for this barrier layer and custom loading of fluorescent molecules into silica shelled plasmonic nanoparticles is available on request.
Product Line | Description | Available Materials | Available Surfaces | CV | Concentration | Available Dried | Buy | nanoComposix University |
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Guaranteed low endotoxin | Gold, silver, platinum, magnetite | Multiple | < 18% | 1 mg/mL | No | See products | Learn more | |
For bioconjugation (lateral flow assays, etc.) | Gold | Multiple | < 15% | Varies; usually 20 OD | Yes | See products | Learn more | |
Widest combination of materials and surfaces | Gold, silver, silica, platinum, magnetite | Multiple | Varies; usually < 15% | Varies | Yes | See products | Learn more | |
Most monodisperse | Gold | PEG-carboxyl | < 5% | 0.05 mg/mL | No | See products | Learn more | |
Do none of these work for you? Request a Custom Nanomaterial | ||||||||
We also offer a variety of nanoparticle characterization services |
Surface | Charge | Characteristics | Available Materials | Buy | NCX University |
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Bare (Citrate) | Easiest standard surface to displace with other molecules. | Gold, silver, platinum | See products | Learn more | |
Aminated (BPEI) | Covalently bound. Conjugatable surface. | Gold, silver | See products | Learn more | |
Carbonate | For biocojugation. Smaller, less complex molecule with a lower affinity to gold nanoparticle surface than citrate. | Gold | See products | Learn more | |
Carboxyl/Lipoic Acid | Covalently bound. Conjugatable surface. | Gold, silver | See products | Learn more | |
Dodecanethiol | Redispersible and stable in non-polar organic solvents. | Gold, silver | See products | Learn more | |
NHS | For quick and easy bioconjugation – no EDC/NHS activation required. | Gold | See products | ||
PEG | Highest stability in aqueous buffers and polar organic solvents. | Gold, silver | See products | Learn more | |
Polystyrene | Hydrophobic surface that allows for dispersion in a wide range of polar organic solvents. | Gold | See products | Learn more | |
PVP | Large polymer surface. Stable in a wide variety of solvents. | Gold, silver, magnetite | See products | Learn more | |
Silica Shell | Greatest solvent compatibility. Preserves plasmonic properties upon deposition. | Gold, silver, silica | See products | Learn more | |
Silica Shell (Aminated) | Conjugatable surface. Greatest solvent compatibility. Preserves plasmonic properties upon deposition. | Gold, silver, silica | See products | Learn more | |
Streptavidin | For convenient bioconjugation of any biotinylated antibody, protein, or oligonucleotide. | Gold | See products | ||
Tannic Acid | Less easily displaced than citrate but stable in more buffers. | Gold | See products | Learn more | |
Do none of these work for you? Request a Custom Surface |