40nm gold nanoparticles

Our 40nm colloidal gold is an aqueous suspension of spherical metallic nanoparticles manufactured to the highest standard to ensure:

  • Uniform spherical shape
  • Narrow size distribution: 40nm ± 4nm, <10% CV
  • Ultra high quality
  • Batch-to-batch consistency
  • High efficiency antibody binding for maximum sensitivity
  • Available at high concentrations to simplify assay development

20nm colloidal gold nanoparticles - TEM data

Furthermore our recently expanded manufacturing capability enables us to provide bulk quantity with guaranteed batch-to-batch consistency.

For large quantities of our 40nm colloidal gold please get in touch with us and we will send you more information and bulk pricing.

40nm colloidal gold nanoparticles - UV-Vis spectrum data

Our colloidal gold nanoparticles are suspended in citrate buffer and they are suitable for:

  • Protein adsorption
  • Oligonucleotide adsorption
  • Surface modifications

Please refer to our custom services for bulk orders or get in contact with us to know more about this product.

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Size distribution and shape

Narrow size distribution and consistent shape is important and preferable for most applications.

A consistent, spherical shape means that particles are less prone to aggregation which can be a problem associated with gold nanoparticles. Furthermore uniform shape ensures consistent binding of antibodies, ensuring reliable assay results.

Our 40nm gold nanoparticles have a narrow size distribution (Figure 1.), with a CV (standard deviation/diameter) of less than 10%.

Each batch of 40nm colloidal gold undergoes TEM analysis to ensure all the requirements are met.

  • Mean diameter 36-44nm
  • SD <4nm
  • CV% <10%

Figure 1. Size distribution of our 40nm gold nanoparticles displaying a narrow size distribution with a CV (standard deviation/diameter) of less than 10%.

Figure 2 below shows electron microscopy images of our gold nanoparticle. Note the consistency of size and shape.

Figure 2.TEM example pictures showing the high consistency of size and shape of Expedeon’ gold nanoparticles

Frequently Asked Questions (FAQs) for Colloidal gold

Ultra high quality 40nm gold nanoparticles, supplied in a range of concentrations for maximum flexibility.

1. What is the shelf life of Expedeon Colloidal gold?

Our colloidal gold is guaranteed to be stable for up to two years from manufacturing in an unopened bottle stored at 4⁰C. It is recommended to use the colloidal gold within six months from opening.

2. What is the best storage condition?

It is recommended to store the colloidal gold at 4⁰C and use them at room temperature. Freezing must be avoided as it leads to irreversible particle aggregation and the formation of a black precipitate.

3. Is it normal for nanoparticles to settle out of solution?

Yes, this can happen especially with larger size gold nanoparticles (40-80nm). The particles might settle at the bottom of the bottle, leaving a clear solution. This process is reversible: the particles can be resuspended by gently inverting the bottle a few times.

4. In which buffer are the nanoparticles provided?

Our colloidal gold nanoparticles undergo a buffer exchange to remove any residual manufacturing products and are suspended in citrate buffer.

5. How are the gold nanoparticles characterized?

Each batch of colloidal gold, both 10nm and 40nm sizes, is analysed by TEM and UV-Visible spectroscopy to ensure high quality standards. Particles specifications, such as mean size, standard deviation and coefficient of variation, are based on more than 100 single nanoparticle measurements.

6. What if I need more concentrated gold nanoparticles for my applications?

Colloidal gold can be centrifuged, but this might lead to aggregation and impossibility to resuspend the nanoparticles. Our range includes gold nanoparticles concentrated up to 20 OD, but upon request we can also manufacture colloidal gold at a higher OD.

Please get in touch for further information.

7. What is your production scale?

We are able to manufacture colloidal gold in bulk quantities to support any scale of operation, still keeping consistent our quality standards.

Please get in touch with us for further information and to request a quote.

Please see here for ordering & shipping information.

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