High sphericity maximizes the available binding surface for antibodies, improving antigen–antibody association kinetics.
Citrate-stabilized gold nanoparticles for passive adsorption
Nano Flow™ citrate-stabilized gold nanoparticles, also referred to as colloidal gold, are optimized for passive adsorption of antibodies, proteins, and other biomolecules. Produced under ISO 9001:2015 certification, they combine exceptional sphericity, narrow size distribution, and intense ruby-red color, delivering reproducibility and sensitivity in lateral flow assays.
Why choose Nano Flow citrate-stabilized nanoparticles ?
Particle size selection for assay formats
Different lateral flow assay designs benefit from different nanoparticle sizes. Based on our internal expertise and benchmarking studies:
| Assay format | Recommended sizes | Key benefits | ||
|---|---|---|---|---|
| Competitive assays | 20 nm – 40 nm | Smaller surface area per particle → fewer antibodies adsorbed → improved sensitivity in competitive formats | ||
| Sandwich assays | 40 nm – 60 nm* – 80 nm | Larger surface area → higher antibody loading → stronger signal and enhanced sensitivity | ||
| *60 nm available on request for large-volume projects. | ||||
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40 nm particles remain the industry standard and Nano Flow’s best-selling product, balancing performance, stability, and large-scale availability (up to 13 L at OD8). |
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| Specification | 20 nm Gold colloids (NF-BG20) | 40 nm Gold colloids (NF-BG40) | 60 nm Gold colloids (NF-BG60, on request) | 80 nm Gold colloids (NF-BG80) |
|---|---|---|---|---|
| Size | 20 ± 3 nm | 40 ± 3 nm | 60 ± 4 nm | 80 ± 5 nm |
| OD | 8 | 8 | 8 | 8 |
| Sphericity | ≥ 99% | ≥ 99% | ≥ 99% | ≥ 99% |
| Odd shapes per 100 particles | ≤ 1 | ≤ 1 | ≤ 1 | ≤ 1 |
| CV on particle sizes | < 15% | < 15% | < 15% | < 15% |
| Suspension | Water | Water | Water | Water |
| Single batch scale | up to 13 L | up to 13 L | available on request | up to 1 L |
| Stability | 18 months | 18 months | 18 months | 18 months |
All Nano Flow gold nanoparticles are supplied with a Certificate of Analysis, including TEM, DLS, and UV-Vis spectroscopy data, to ensure compliance with specifications and reproducibility across batches.
