"IVD‑READY" Gold Nanoparticles Size Optimization Kit for Biosensing

Optimize your in-vitro diagnostic assay with one kit containing four carefully selected sizes of monodisperse spherical gold nanoparticles. The "IVD‑READY" Size Optimization Kit enables rapid comparison of nanoparticle diameter in lateral-flow assays, colorimetric biosensors, immunoassays, and other diagnostic formats.

Testing several sizes under identical assay conditions helps identify the nanoparticle that provides the best balance of visual signal, sensitivity, conjugate stability, membrane flow, and assay specificity.

Kit contents

• Four selected sizes of "IVD‑READY" spherical gold nanoparticles: 

  20, 40, 80 and 100nm, with narrow size distribution

  CoV (coefficient of variation): ≤ 5%

  Polydispersity index: PdI ≤ 0.1

• Equal quantity of each nanoparticle size
• Choice of citrate-coated or PEG‑5000‑carboxylate-coated formulation
• Supplied as aqueous colloidal dispersions
• Certificate of Analysis provided for each size

Why optimize nanoparticle size?

Gold nanoparticle size can significantly affect the performance of an IVD assay. Smaller particles offer a higher surface-area-to-volume ratio and may be advantageous where reduced steric hindrance, efficient reagent interaction, or rapid flow is important. Larger particles generally provide stronger visible color and light scattering, which can improve visual readout, but may require careful optimization of conjugation conditions and membrane performance.

The four sizes included in this kit allow developers to compare these size-dependent effects directly and select the most appropriate gold nanoparticle format for their specific assay design.

Surface-coating options

Citrate-coated gold nanoparticles are suitable for workflows based on passive adsorption of antibodies, proteins, or other biomolecules onto the gold surface. They are a flexible choice for conventional lateral-flow conjugate development and screening.

PEG‑5000‑carboxylate-coated gold nanoparticles provide carboxyl functional groups for controlled covalent attachment of antibodies or other amine-containing biomolecules using standard coupling chemistries. The PEG spacer can help improve colloidal stability and provide a more controlled surface for conjugation.

This flexibility lets align your conjugation strategy with assay format, stability requirements, and IVD regulatory needs. Find out Why is Surface Chemistry a "real product" for Gold Nanoparticles.

Applications

• Lateral-flow assay development and optimization
• Antibody–gold nanoparticle conjugate screening
• Rapid antigen and antibody tests
• Colorimetric immunoassays
• Biosensor and point-of-care diagnostic development
• Comparative evaluation of signal intensity, flow behavior, sensitivity, and background

Learn more about Gold Nanoparticles in Biosensing and Personalized Medicine.

IVD size-selection guidance

• Smaller diameters: Useful for assessing rapid membrane migration, high relative surface area, and reduced steric effects during biorecognition.
• Intermediate diameters: Often provide a practical balance between optical visibility, conjugate performance, and flow in lateral-flow formats.
• Larger diameters: Useful when stronger visible color, enhanced scattering, or higher visual contrast is desired; assay conditions should be optimized to maintain efficient flow and low background.

High monodispersity for reliable diagnostics

Tightly controlled monodispersity ensures uniform localized surface plasmon resonance, generating a strong, consistent red signal and predictable optical response in IVD biosensing assays. The narrow size distribution and clean, reactant‑free surface chemistry support robust antibody and biomolecule conjugation, enabling sensitive, reproducible detection of proteins, antibodies, and nucleic acids in clinical diagnostics and research applications. Explore more about the Benefits of monodisperse Gold Nanoparticles for LFAs.

Customization and OEM Options

Custom size combinations, concentrations, volumes  and PEG spacer lengths may be available on request. Contact us to assemble a kit tailored to your diagnostic-development workflow.

Storage and Stability

- Citrate‑coated: store at 4–25 °C, do not freeze. Gently shake before use.

- PEG‑COOH: store at 2–8 °C, do not freeze. Gently shake before use.

Under these conditions, products are typically stable for at least 12 months. For long‑term storage, check UV‑Vis spectra periodically to confirm colloidal and optical stability.

Safety and Handling

NanoBrand does not guarantee the suitability of its products for any particular application. It is the customer’s responsibility to ensure that the product is appropriate and permitted for the intended use, in accordance with applicable regulations and internal quality systems. Please consult our Terms of Service and follow institutional guidelines for the safe handling and disposal of nanomaterials.

Discover Gold Nanoparticles - Spherical, Citrate Surface and Gold Nanostars.