gold colloid bottles
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Gold Colloid

BBI Solutions trusted colloidal gold nanoparticles are used in over 500 million assays a year. We set the standard for your assay needs, batch after batch.

Setting the Gold Standard for Nanoparticles 

Every year our colloidal gold nanoparticles are used in over 500 million assays globally and are renowned for offering exceptional assay consistency levels. Our proprietary manufacturing technique allows for the production of large volume batches of gold to a high level of reproducibility of size, dispersion and shape, and we maintain this through tight quality control release specifications. This ensures a firm foundation for conjugation and peace of mind that your assay will provide reliable results.  

BBI Solutions have been manufacturing high-quality gold nanoparticles for over 30 years, making us the trusted partner for thousands of researchers, lateral flow assay developers and manufacturers worldwide. 

 

Delivering exceptional quality gold colloid, time after time 

At BBI we understand our customers have different requirements, so we offer a range of gold nanoparticle sizes from 2nm to 250nm to cater to those needs, whatever the application.   

Our proprietary manufacturing technique delivers: 

Uniformity 
With ≤5% odd shapes and a CV of ≤8%, the uniform shape and size of BBI gold ensures even antibody binding, giving reliable results in your assay. 

High stability

BBI particles are proven stable for at least twelve months and are supplied with a minimum of three month’s expiry. Stable particles ensure a settled testing regime, saving you time and wastage.

Scalability
Our batch sizes go up to 340l (40nm) to ensure you have a continuous supply.

Quality
 BBI gold must pass strict quality procedures before it's released to our customers, guaranteeing impressive performance characteristics at scale. 

Gold nanoparticle applications 

BBI Solutions’ gold nanoparticles are renowned for their use in lateral flow tests; however, the use of nanoparticles ranges from health and material technology to the environment and energy sectors as detailed in the table below. 

Size range of nanoparticles 

Applications 

Small (2nm -15nm) 

Immunohistochemistry; Light Microscopy; High magnification TEM; Microarray platforms
Biosensors 

Medium (20nm – 80nm) 

Lateral flow assays 

TEM and SEM; SERRS; DNA detection 

Large (100nm – 250nm) 

Flow cytometry; SERRS; Forensic science 

 

BBI Solutions gold nanoparticles for rapid diagnostic assays:

 

20nm Gold Nanoparticles

40nm Gold Nanoparticles

60nm Gold Nanoparticles

80nm Gold Nanoparticles

Average Diameter

19.0 – 21.0nm

37.0 – 43.0nm

57.0 – 63.0nm

77.0 – 85.0nm

Maximum acceptable % CV

8%

Number of odd shapes per 100 particles

≤5

≤10

Optical density @520nm (using a 1 cm pathlength)

  • Bulk available at OD1
  • Up to 50mL available at OD 5/10
  • Bulk available at OD1
  • Bulk available at OD 4.5 – 5.0
  • Up to 50mL available at OD10

Bulk available at OD1

Bulk available at OD1.0 at 555nm

Batch scale

Up to 110L at OD1

Up to 340L at OD1

Up to 64L at OD1

Up to 64L at OD1

Capping agent

Citrate

Presentation matrix

Suspended in H2O, no preservative


Advantages of outsourcing 
There are many hidden costs in producing gold nanoparticles and conjugates in-house. By outsourcing manufacture to BBI, you can benefit from: 

More R&D time
Valuable R&D time is freed up to concentrate on the development of your assay systems  

More tests per litre of gold
Using BBI gold colloid results in more tests per volume of conjugate, because consistent gold means less waste 

A faster route to market
By using BBI gold you can avoid delays caused by using a poor, inconsistent gold label, and commercialise your assay faster 

Please contact our Customer Services Team directly to discuss your requirements on tel:+44 (0) 1495 363000 or alternatively you can submit an enquiry here.

 

Ordering information - Gold colloid (EM grade)

Gold Nanoparticle Size Product code Quantity
5nm Gold Nanoparticles

EM.GC5/4
EM.GC5/7

20ml
100ml
10nm Gold Nanoparticles EM.GC10/4
EM.GC10/7
20ml
100ml
15nm Gold Nanoparticles EM.GC15/4
EM.GC15/7
20ml
100ml
20nm Gold Nanoparticles EM.GC20/4
EM.GC20/7
20ml
100ml
30nm Gold Nanoparticles EM.GC30/4
EM.GC30/7
20ml
100ml
40nm Gold Nanoparticles EM.GC40/4
EM.GC40/7
EM.GC40/8
EM.GC40SPL/7
EM.GC40SPL/8

20ml
100ml
500ml
100ml (OD4.5-5)
500ml (OD4.5-5)

50nm Gold Nanoparticles EM.GC50/4
EM.GC50/7
20ml
100ml
60nm Gold Nanoparticles EM.GC60/4
EM.GC60/7
20ml
100ml
80nm Gold Nanoparticles EM.GC80/4
EM.GC80/7
20ml
100ml
100nm Gold Nanoparticles EM.GC100/4
EM.GC100/7
20ml
100ml
150nm Gold Nanoparticles EM.GC150/4
EM.GC150/7
20ml
100ml
200nm Gold Nanoparticles EM.GC200/4
EM.GC200/7
20ml
100ml
250nm Gold Nanoparticles EM.GC250/4
EM.GC250/7
20ml
100ml

 

Gold Starter Packs

Are you using gold for the first time, or trying a new process and are unsure of which size particle to purchase? Our gold starter packs allow a comprehensive evaluation, comprising 100ml and/or 20ml each of a selection of our gold nanoparticles.

Product Product code Quantity
Gold Colloid 20nm / 40nm / 60nm / 80nm GCIKITDIAG/4 20ml
Gold Colloid 20nm / 40nm / 60nm / 80nm GCIKITDIAG/7 100ml
Gold Colloid 5nm / 10nm / 20nm / 40nm GCIKITLIFE/4 20ml

 

Ordering information - Gold colloid HD series

High OD gold can be used to provide dense uniform mono-layers of gold particles on substrates and can also simplify the conjugation procedure by removing the concentration steps. This saves time, reduces costs and ensures waste is minimised.

Gold Nanoparticle Size Product code Quantity
20nm Gold Nanoparticles - OD5 HD.GC20.OD5/10
HD.GC20.OD5/50
10ml
50ml
20nm Gold Nanoparticles - OD10 HD.GC20.OD10/10
HD.GC20.OD10/50
10ml
50ml
40nm Gold Nanoparticles - OD10 HD.GC40.OD10/10
HD.GC40.OD10/50
10ml
50ml

 

Gold Colloidal Products

If you require any further product specific technical information or datasheets regarding our gold colloid products please submit your request to our technical team here 

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Gold Colloid FAQs

Our team are here to help! If you can’t find the answer you are looking for contact us.

The gold colloid will remain stable until at least the expiry date stated on the label if the colloid is kept unopened at the recommended storage temperature (2-8°C). BBI’s EM Grade gold colloids are assigned a 12-month expiry date from the date of manufacture (excepting 15nm and 20nm gold colloids which are given an 18-month and a 15-month expiry date). Stability was ascertained by real-time stability studies for the shelf life of the product.

Using within one month of opening is what is recommended by BBI (and is the practice BBI follows in-house) and is due to the lack of preservative agents (such as sodium azide) in the gold colloid. When the bottle is opened the gold colloid is exposed to contaminants, both from the air and from any pipette tips etc. inserted in the liquid. This contamination can lead to microbial growth within the colloid.

For best results (to help avoid particle aggregation) the end-user should avoid pipetting directly from the bottle. Instead they should pour out a small aliquot into a suitable container
(borosilicate glass is recommended) and pipette from this. This protects the bulk solution from cross-contamination and potential introduction of particulate matter (such as dust) which can cause particle aggregation. It is recommended that the bulk volume of gold colloid be kept in its original container.

No. BBI’s gold colloids and conjugates are not suitable for injection, administration by mouth or any other in-vivo application. The products are supplied for in vitro use only, to be used for research and/or further manufacturing purposes, and not for use in humans or animals.

Any use of the products for off-label, in-vivo applications is strictly done at the customer's own risk. BBI does not accept responsibility for the misuse of any of its products.

The exact method is proprietary; however, it can be shared that the gold nanoparticles are formed by the citrate reduction of a gold chloride solution.

The gold nanoparticles are formed by the citrate reduction of a gold chloride solution. This leaves the gold particles with a citrate shell which confers a net negative charge upon the particles, allowing them to repel each other and remain in solution. No other stabilising agents or preservatives are added to the gold colloid following the manufacture process.

The smallest gold nanoparticle that BBI offers is 5nm in diameter and the largest is 250nm. The particle sizes available are: 5nm, 10nm, 15nm, 20nm, 30nm, 40nm, 50nm, 60nm 80nm, 100nm, 150nm 200nm and 250nm.

The gold nanoparticles are provided suspended in purified water (as made), with only residual chemicals left from manufacture also present in solution.

No. Frozen colloids precipitate and become clear in colour with visible aggregates present. This process is irreversible. Ideally colloids should be stored in the door of a fridge or away from the chillers in a cold room to prevent accidental freezing.

BBI offers more concentrated versions of the 20nm and 40nm gold colloids, referred to as the HD Grade range. In addition to the standard concentration (OD520 1) products, OD520 5 (20nm only) and OD520 10 (20nm and 40nm) products are available in 10ml and 50ml pack sizes. HD Grade gold colloids do not have an expiry date applied to them as BBI has not carried out a stability study on this product range. The batch size of the product range is limited to 50ml. For these reasons, the HD Grade colloid range is not suitable for use in the making of gold conjugates for lateral flow test manufacture or any other kind of regulated manufacture.

As standard, 40nm gold colloid is manufactured at a concentration of OD520 ~4.5. This undiluted colloid is available to purchase from BBI under the product code EM.GC40 SPL. As this colloid has not been through a concentration process, it retains its shelf life of 12 months from the date of manufacture and is available in batch sizes greater than the HD range (the batch size can be as large as 80 litres).

As the concentration of the EM.GC40 SPL is close to OD520 5, it can be used as an alternative to a HD Grade 40nm gold colloid at OD520 5, with the benefit that it is a product with an assigned 12- month expiry date (from the date of manufacture) and a larger maximum batch size. The EM.GC40 SPL products are suitable for use in lateral flow manufacture and development. Our HD products are also suitable for such applications but discussion around your specific assay and single batch volume requirements are recommended.

Gold nanoparticles ≥40nm in diameter have too much mass for the negative charge on the particle surface to keep them suspended. These particles will sink out of solution and settle at the bottom of their container. Colloids that have settled in this way can be resuspended by inversion.

BBI’s gold colloid is manufactured at our ISO 13485:2015 certified facility in Crumlin, South Wales, UK.

•BBI particles are proven stable for at least twelve months and are supplied with a minimum of three month’s expiry. Stable particles ensure a settled testing regime, saving you time and wastage
•Uniform shape and standard size with a low coefficient of variation. This ensures even antibody loading giving reliable results in your assay.
•Manufacturing scale. Batch sizes of up to 350+ litres to ensure you have a continuous supply.

If the gold colloid is to be diluted for use, it is recommended to use purified water of a comparable purity (resistivity ≥18MΩ) to that used in the manufacture process

The gold colloid is shipped at ambient temperature.

The risk of the colloids freezing far outweighs the risk of the colloids being exposed to elevated temperatures. If the colloids freeze (even if only for a short time) they will completely and
irreversibly collapse. In contrast, the colloids tolerate being exposed to elevated temperatures well for a short period of time.

We do recommend that the colloid is kept at 2-8°C for long term storage, however over a short period of time (such as a few days, which will be the case during international shipping) the
colloid will be fine at higher temperatures. Adding cold packs to the shipping carton will increase the risk of freezing, which should be avoided at all costs.

BBI have assigned an expiry date to the product based on our real time stability studies. The studies did not test the colloid to the point of failure. It is therefore possible that, if the product has been stored and handled correctly, the material could be successfully used after the expiry date. As the product is beyond the recommended BBI expiry, the performance stated on the datasheet is not guaranteed and the product would need to be assessed to ensure it is still meeting the requirements of the specific application.

BBI GC5-80nm all have an Optical density (OD) stated on the datasheet, these will be read in a UV-Vis spectrophotometer at A520nm. For particle sizes above 80nm, the peak of the particles becomes very poorly defined and in is hard to ascertain a consistent wavelength at which to read the OD from batch to batch.

Non-HD grade gold colloids are available in 20/100/250/1000ml pack sizes. HD colloids are available in 10/50ml pack sizes.

Good gold versus bad gold 

BBI’s unique manufacturing technique allows for the production of large batches of gold to a high level of reproducibility of size, dispersion and shape. This ensures a firm foundation for conjugation and peace of mind that your rapid assay will provide reliable results. 

To help understand the advantages of using high quality gold. Take a look at our movie

Gold Nanoparticle starter packs 

Are you using gold for the first time, or trying a new process and are unsure of which gold nanoparticles size to purchase? 

Our gold starter packs provide a range of particle sizes to allow a comprehensive evaluation, comprising 100ml each of a selection of our gold nanoparticles.  

High OD Gold 

Our High OD colloid can be used to provide dense uniform monolayers of gold particles on substrates and can also simplify the conjugation procedure. 

By removing centrifugation steps in the concentration process, there is an opportunity to make potential savings in time, reduced labour costs and ensure waste is minimised during the R&D phase of a project. 

Our High OD gold nanoparticles are available as 20nm and 40nm and at concentrations of OD5 and OD10, and are available ONLY in 10ml or 50ml pack sizes. 

 

 

Gold Colloid Technical Documents

If you require any further product specific technical information or datasheets please submit your request to our technical team here 

Last updated: 08/03/2021

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