manufactured · input

Colloidal Gold Nanoparticles (AuNPs)

Uniform spherical gold nanoparticles (20–80 nm) suspended in citrate buffer, used as the colorimetric signal label in lateral flow immunoassays. Made by reducing tetrachloroauric acid (HAuCl4) with sodium citrate. The red/pink color of COVID antigen tests, pregnancy tests, and flu tests comes from AuNP conjugates.

Source countries

Companies

Goods affected

Claims on record

What depends on it

Goods that need this input

1 essential American goods rely on colloidal gold nanoparticles (aunps) somewhere upstream in their supply chain.

Health

Diagnostic tests and lab supplies

PCR reagents, rapid antigen tests, lab analyzers, and sample collection kits for clinical and public health testing.

Where it comes from

Source countries

Share of global supply, by country.

Country	Share of supply
CNChina	40%
USUnited States	35%
GBUnited Kingdom	15%

Who makes it

Supplier companies

3 companies produce colloidal gold nanoparticles (aunps).

BBI Solutions

HQ GB20% share

UK-based manufacturer of gold colloid and lateral flow assay reagents; headquartered in Crumlin, South Wales; ISO 13485:2015 certified; supplies gold nanoparticles used in over 500 million diagnostic assays globally per year; pioneer in commercial colloidal gold production for 30+ years; offers proprietary large-batch manufacturing with high particle uniformity; acquired IBEX Technologies (Canada) in 2024 and Biotez GmbH (Germany) to expand biochemistry capabilities; key supplier to Roche, Abbott, Siemens Healthineers and other major IVD manufacturers

nanoComposix (Fortis Life Sciences)

HQ US12% share

San Diego, California-based gold and silver nanoparticle manufacturer; acquired by Fortis Life Sciences (~2020); produces highly monodisperse gold nanoparticles for lateral flow assays, immunodiagnostics, and research; reference manufacturer for many gold NP characterization standards; known for ultra-uniform particle sizing critical for consistent assay performance; supplies to diagnostic kit developers and OEM test manufacturers globally

Cytodiagnostics Inc.

HQ CA5% share

Canadian manufacturer (Burlington, Ontario) of gold and silver nanoparticles for lateral flow assays and immunodiagnostics; produces gold colloid in standard sizes (3-200nm) and offers conjugation services; offers DIY LFA conjugate kits and bulk gold nanoparticle supply to diagnostic manufacturers; significant online presence targeting smaller test developers and academic researchers

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