This product is prepared as a suspension in a citrate buffer. It can be further diluted with water. Avoid diluting further with buffers containing other electrolyte salts such as sodium chloride. Due to the gold nanoparticle surface charge, aggregation and color changes will occur.
741965
Gold nanoparticles
20 nm diameter, OD 1, suspension in citrate buffer
Synonym(s):
Au NP, Gold Colloid
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| Size/SKU | Availability | Price |
|---|---|---|
25 mL | Available to ship TODAYfromMILWAUKEE | $152.00 |
100 mL | Available to ship TODAYfromMILWAUKEE | $483.00 |
About This Item
Quality Segment
form
nanoparticles, suspension
contains
Proprietary Surfactant as stabilizer
concentration
~6.54E+11 particles/mL
OD
1
diameter
20 nm
λmax
518-522 nm
PDI
<0.2
storage temp.
2-8°C
SMILES string
[Au]
InChI
1S/Au
InChI key
PCHJSUWPFVWCPO-UHFFFAOYSA-N
General description
Gold nanoparticles (AuNPs) are versatile materials widely used in biomedical sciences and electrochemical sensor based applications. AuNPs are tunable nano-materials with excellent thermo-mechanical properties, high surface area, and low toxicity.
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.
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.
Citrate stabilized AuNPs can be used for a variety of applications such as:
- neutrophil labeling for monitoring the effect of different drugs
- immobilization of proteins for biosensor applications
- nano-carrier for drug delivery system for the release of hydrophobic drugs.
Legal Information
Product of CytoDiagnostics, Inc.
1 of 1
This Item | |||
|---|---|---|---|
| form nanoparticles, suspension | form nanoparticles, suspension | form nanoparticles, suspension | form nanoparticles, suspension |
| OD 1 | OD 1 | OD 1 | OD 1 |
| concentration ~6.54E+11 particles/mL | concentration ~6.0E+12 particles/mL | concentration ~3.8E+9 particles/mL | concentration ~7.2E+10 particles/mL |
| PDI <0.2 | PDI <0.2 | PDI <0.2 | PDI - |
| Quality Level 100 | Quality Level 100 | Quality Level 100 | Quality Level 100 |
| contains Proprietary Surfactant as stabilizer | contains Proprietary Surfactant as stabilizer | contains Proprietary Surfactant as stabilizer | contains - |
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Storage Class
12 - Non Combustible Liquids
wgk
nwg
flash_point_f
Not applicable
flash_point_c
Not applicable
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What is the best solution to dilute the gold nanoparticle suspension? Is 2mM sodium citrate appropriate?
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How can I determine the shelf life / expiration / retest date of this product?
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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/418/501/product-dating-information-06-25-mk.pdfHelpful?
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What is the recommended temperature range for using your 10 nm gold nanoparticles? Additionally, is there a temperature limit beyond which they may aggregate or lose stability?
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It is recommended to use these colloidal gold nanoparticles within the temperature range of 4°C to 25°C. Below 4°C, the particles will irreversibly aggregate and become unsuitable for further use. The upper limit for thermal stability has not been determined for these particles.
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How is shipping temperature determined? And how is it related to the product storage temperature?
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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
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The AuNPs in citrate do not change color when with NaCl. What can I do? Do you have any recommendation of what protocol can I use to functionalize citrate AuNPs 20nm?
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The color change of AuNPs when mixed with NaCl is typically due to the aggregation of AuNPs. However, this product contains citrate buffer as a stabilizer, so a small amount of NaCl will not lead to aggregation. Increasing the amount of NaCl or performing a solvent exchange to remove the citrate buffer may induce a color change, but this is not recommended as the aggregated AuNPs may not be able to be re-dispersed. Unfortunately, no protocol is available to functionalize the AuNPs.
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What is the molarity of this solution (ref: 741965)?"
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The concentration for this product is listed as ~6.54E+11 particles/mL. The concentration in g/mol is not determined.
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My solution of 5nm gold nanoparticles has turned from red to purple. This would indicate aggregation. What caused this and how can I reverse the aggregation? The nanoparticles are stored in a fridge at 5 degrees C.
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The information below regarding the color change and aggregation is provided by the manufacturer:
The gold nanoparticle solution turns violet when I add salt-containing buffer. Why is that?
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 are present, this energy barrier is too strong for interaction to occur between particles. However, upon the 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 the color of the solution.Gold Nanoparticle Aggregation
The aggregation state of gold nanoparticles has an effect on their optical properties. This fact can be used to monitor gold nanoparticle stability, both over time, and upon the addition of salt-containing buffers, which at high enough concentrations cause particle aggregation, figure 5. The red-shift in absorption maximum caused by aggregation, or particles in close proximity, has successfully been utilized in many assays as a detection mechanism.See the image below for details on the effects of aggregation on color change and wavelength.
To discuss this further, please we kindly ask you to navigate to the link https://www.sigmaaldrich.com/techservice and click on "Report Product Issues" under the Products Section with all the required information so that a member of our team can reach out to you to assist further. Thank you.
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Which technique is used for the synthesis of these Gold nanoparticles?
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This product has a quality level 100. The preparation and synthesis is proprietary for products with a quality level under 400.
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Which gold nanoparticle size should I choose for my application?
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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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How do you attach gold nanoparticles to glass?
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To view the procedure on how to attach gold nanoparticles to glass please view information in the reference - Journal of Atomic, Molecular, and Optical PhysicsVolume 2012 (2012). Article ID 683830, 6 pagesdoi:10.1155/2012/683830
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