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Sigma-Aldrich

Gold nanoparticles

40 nm diameter, OD 1, stabilized suspension in citrate buffer

Synonym(s):

Au NP, Gold Colloid

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About This Item

MDL number:
MFCD00003436
UNSPSC Code:
12352302
PubChem Substance ID:
329765547
NACRES:
NA.23
Pricing and availability is not currently available.

Quality Level

100

form

nanoparticles
suspension

contains

Proprietary Surfactant as stabilizer

concentration

~7.2E+10 particles/mL

OD

1

diameter

40 nm

λmax

526-531 nm

PDI

<0.2

storage temp.

2-8°C

SMILES string

[Au]

InChI

1S/Au

InChI key

PCHJSUWPFVWCPO-UHFFFAOYSA-N

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Application

Ideal for adsorption of thiolated ligands such as oligonucleotides and polyethylene glycols. Also, due to the increased stability, these gold nanoparticles are ideal for use in physical and optical applications. Note: This product is not ideal for protein adsorption. For gold nanoparticles suitable for adsorption of proteins and other ligands for conjugate development, please see our gold nanoparticles stabilized in PBS.

This material is highly monodisperse (<12% variability in size and shape), and provides significantly improved surface reactivity. Applications include Surface Enhanced Raman Lables, Sensing/Detection, Biological Targeting, Plasmonics and Electronics.

Legal Information

Product of CytoDiagnostics, Inc.

Storage Class Code

12 - Non Combustible Liquids

WGK

nwg

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

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Certificates of Analysis (COA)

Lot/Batch Number
MKCW9792
MKCW6832
MKCV5915
MKCS9653
MKCR9951

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Sanchi Maithani et al.
Analytical chemistry, 92(5), 3998-4005 (2020-02-06)
We report on the development of a simple, linear optical cavity-based system combining evanescent wave (EW) with high-sensitive cavity ring-down spectroscopy (CRDS) technique using a diode laser at 644 nm and a right-angled prism for evanescent field generation on prism

Questions

1–10 of 13 Questions  

  1. How can I determine the shelf life / expiration / retest date of this product?

    1 answer

    1. If this product has an expiration or retest date, it will be shown on the Certificate of Analysis (COA, CofA). If there is no retest or expiration date listed on the product's COA, we do not have suitable stability data to determine a shelf life. For these products, the only date on the COA will be the release date; a retest, expiration, or use-by-date will not be displayed.
      For all products, we recommend handling per defined conditions as printed in our product literature and website product descriptions. We recommend that products should be routinely inspected by customers to ensure they perform as expected.
      For products without retest or expiration dates, our standard warranty of 1 year from the date of shipment is applicable.
      For more information, please refer to the Product Dating Information document: https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/marketing/global/documents/449/386/product-dating-information-mk.pdf

      Helpful?

  2. How is shipping temperature determined? And how is it related to the product storage temperature?

    1 answer

    1. Products may be shipped at a different temperature than the recommended long-term storage temperature. If the product quality is sensitive to short-term exposure to conditions other than the recommended long-term storage, it will be shipped on wet or dry-ice. If the product quality is NOT affected by short-term exposure to conditions other than the recommended long-term storage, it will be shipped at ambient temperature. As shipping routes are configured for minimum transit times, shipping at ambient temperature helps control shipping costs for our customers. For more information, please refer to the Storage and Transport Conditions document: https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/marketing/global/documents/316/622/storage-transport-conditions-mk.pdf

      Helpful?

  3. Can the Gold nanoparticles be frozen?

    1 answer

    1. No, the Gold nanoparticles should not be frozen.  If frozen, the gold nanoparticles will irreversibly aggregate, turning the solution clear.

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  4. What is the shape of the gold nanoparticles?

    1 answer

    1. The majority (>95%) of the gold nanoparticles are spherical.

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  5. Why does my gold nanoparticle solution turn violet when I add salt containing buffer?

    1 answer

    1. Due to repulsive forces arising from the surface charge of gold nanoparticles, an energy barrier must be overcome for individual particles to interact. When no (or small) amounts of electrolytes such as NaCl is present, this energy barrier is too strong for interaction to occur between particles. However, upon addition of NaCl this energy barrier is reduced allowing the gold nanoparticles to interact and aggregate. This aggregation causes a phenomenon called surface-plasmon coupling which changes the adsorption maximum of light to a higher wavelength resulting in a change in color of the solution.

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  6. My gold nanoparticles settle out of solution upon storage. Is this normal?

    1 answer

    1. Settling of gold nanoparticles on the bottom of the storage flask is completely normal and is especially common for larger sized particles, which settles at greater speed. Settling does not affect the performance of the particles. Prior to use, simply swirl the solution to properly disperse your gold nanoparticles and obtain a homogenous solution.

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  7. Do I need to wash my gold nanoparticles?

    1 answer

    1. For most applications, our gold nanoparticles can be used without any additional washing steps. If you have a sensitive application that requires additional washing the best way to do so is by either centrifugation or filtration.

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  8. How do you attach gold nanoparticles to peptides and peptide conjugates?

    1 answer

    1. To view information on how to attach gold nanoparticles to peptides and peptide conjugates, please view the information in the reference - Rosenthal, S. J. and Wright, D. W. (Eds.). (2005), p. 91-92. NanoBiotechnology Protocols. New Jersey. Humana Press.

      Helpful?

  9. How do you attach gold nanoparticles to oligos?

    1 answer

    1. To attach gold nanoparticles to oligos please view the information in the attached reference - Bioconjug Chem. 2011 Apr 20;22(4):794-807. Epub 2011 Mar 28.

      Helpful?

  10. Which gold nanoparticle size should I choose for my application?

    1 answer

    1. The size of gold nanoparticle to use is very depandent upon the intended application. Generally, smaller particles offer better sensitivity in applications such as immunogold labeling due to less steric hindrance and the ability to bind more gold nanoparticles to the desired target. Small gold nanoparticles are less visible than larger particles, however, which must also be taken into account.As an application example, particles with a size between 30-50nm are particularly useful for the development of rapid tests such as lateral flow assays.

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1–10 of 13 Questions  

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