Colloidal Gold for Lateral Flow (10nm) is Attogene’s 10nm colloidal gold: highly stable, uniform 10 nm gold nanoparticles (catalog AU2012) for preparing antibody and protein conjugates for lateral flow assays. Particles measure 10 nm ± 1.5 nm in diameter with an absorption maximum of 514–520 nm, and the gold can be supplied anywhere from 1 OD to 100 OD.
The quality of a gold conjugate is critical to successful lateral flow test manufacturing. This product is made in Attogene’s facility in Austin, Texas, which supports rapid turnaround and batch-to-batch consistency, and it is functionally tested in lateral flow. Bulk pricing and manufacturing supply contracts are available.
Key Features
- Tight size control: 10 nm ± 1.5 nm particle diameter.
- Uniform particles: Attogene colloidal gold has a size distribution CV below 12% and more than 95% spherical particles.
- Low lot-to-lot variation: batch-to-batch variation of ±2 nm, so optimized conjugation conditions carry over to new lots.
- Highest particle count in the line: 2.5–8.6 × 10¹² particles/mL at 1 OD, compared with 1.3–2 × 10¹¹ for the 30 nm product.
- Functionally tested in a lateral flow format.
- Flexible concentration: standard 1 OD, with 1–100 OD available on request.
Specifications
Each 10nm colloidal gold order is supplied at the standard 1 OD unless you arrange otherwise. Specifications for the 1 OD product (catalog AU2012-01):
- Particle diameter: 10 nm ± 1.5 nm
- Absorption maximum: 514–520 nm
- Particles per mL: 2.5–8.6 × 10¹²
- Gold concentration: 5.7–6.0 × 10⁻² mg/mL
- Molar concentration: 0.4–1.4 × 10⁻⁸ mol/L
- Zeta potential: −50 mV
- pH: 7.5
- Pack sizes: 30 mL, 100 mL, 500 mL and 1 L
- Storage: 2–25 °C. Do not freeze; freezing causes irreversible aggregation and destroys the product.
For a different OD or larger quantities, contact sales@attogene.com.
Who It’s For
- Lateral flow assay developers who prepare their own antibody–gold conjugates and want a well-characterized 10 nm particle.
- R&D teams screening particle size alongside pH, antibody loading and gold concentration. The same line is available as 30nm, 40nm and 60nm Colloidal Gold.
- Test manufacturers who need consistent lots and supply agreements for scale-up.
How to Use 10nm Colloidal Gold in Your Assay
A summary of Attogene’s spec sheet and Gold Conjugation Technical Guide for passive adsorption of antibodies to gold:
- Disperse the gold. Bring it to room temperature and shake vigorously for 30 seconds before each use.
- Prepare the antibody. Buffer-exchange into 10 mM HEPES or your chosen buffer. BSA, gelatin, glycerol, Tris, glycine and sodium azide compete for or destabilize the gold surface.
- Screen pH. In a 96-well plate, add 100 µL of 1 OD gold per well, then 10 µL of 22 mM buffer from pH 5.5 to 10 (MES 5.5–6.5, HEPES 7.0–7.5, borate 8.0–10) and 10 µL of antibody at 100 µg/mL. Incubate 15 minutes at room temperature, then add 25 µL of 1.5 M NaCl. Wells that stay red are stable; a shift to purple-gray means aggregation.
- Titrate the antibody. At the chosen pH, test a dilution series to find the minimum amount of antibody that stabilizes the gold against salt.
- Scale up, block and wash. Add antibody to gold (never the reverse), block with BSA, then remove free antibody by centrifugation or tangential flow filtration.
- Test function. Run a dot-spot test on blank lateral flow strips, testing each antibody as both capture and detector.
Documents (PDF): 10 nm spec sheet (AU2012-01) and Gold Conjugation Technical Guide.
Particle Size and Assay Performance
Particle size is one of several variables that shape how a lateral flow test looks and reads. In Attogene’s article The Impact of Colloidal Gold on Lateral Flow Optimization, conjugates made from different gold sizes gave clearly different visual results in a competitive assay, and gold concentration and the reader used also affected readability.
Attogene’s conjugation guide names 40 nm as the standard starting point for lateral flow, so a 10 nm particle is best treated as one option to compare in your own format. Run the pH screen and antibody titration separately for each size rather than carrying conditions over. The guide’s centrifugation table covers 20, 40 and 60 nm particles, with the required g-force rising as size falls, so set pelleting conditions for 10 nm conjugates empirically.
Prefer a ready-made conjugate? See Protein A Colloidal Gold and Streptavidin Colloidal Gold. For nucleic acid dipstick work, the Universal Lateral Flow Assay Kit (Particles Not Included) is supplied without detection particles so you can add your own gold or other reporter.
Frequently Asked Questions
What concentration is the gold supplied at?
Standard products are 1 OD. Attogene can supply 10nm colloidal gold from 1 OD to 100 OD; contact sales for concentrated material or larger volumes.
How should I store it?
Store at 2–25 °C and never freeze. Shake vigorously for 30 seconds before each use so the particles are fully dispersed.
Is this gold already conjugated?
No. It is unconjugated gold for making your own conjugates. Attogene’s Protein A and streptavidin gold products are ready-made alternatives.
How consistent is it from lot to lot?
Attogene reports batch-to-batch variation of ±2 nm, so conditions optimized on one lot of 10nm colloidal gold should carry over to the next. Attogene still recommends conjugating each antibody to several batches of gold and comparing them side by side on blank strips.
Can Attogene make the conjugate for me?
Yes. Attogene’s lateral flow services include antibody pair screening, colloidal gold conjugation, pad and buffer optimization, prototyping and scale-up.
For research use only. Not for use in diagnostic procedures. Questions? Call 512-333-1330 or email sales@attogene.com.
For larger sizes contact us: sales@attogene.com
