40 nm IVD‑READY Gold Nanoparticles for Biosensing

NanoBrand 40 nm IVD‑READY Gold Nanoparticles are optimized for IVD assays that require precise quantitative readouts and excellent conjugation control. Their 40 nm core size provides well‑defined plasmonic color with outstanding stability and low background, making them ideal for high‑sensitivity LFAs, multiplexed colorimetric IVD tests, and instrumented biosensing platforms where analytical performance, specificity, and reproducibility are critical for diagnostic accuracy and regulatory‑ready validation.

- Application focus: IVD biosensing, rapid tests, ELISA, microfluidics, biosensors, LFAs

- Format: Aqueous colloidal suspension, ready for bioconjugation

- Grade: Research and development, suitable for transition to commercial IVD use

High monodispersity for reliable diagnostics

Core diameter: 40 nm, narrow size distribution

CoV (coefficient of variation): ≤ 5%

Polydispersity index: PdI ≤ 0.1

Tightly controlled monodispersity ensures uniform localized surface plasmon resonance, generating a strong, consistent red signal and predictable optical response in IVD biosensing assays. This uniformity improves lot‑to‑lot reproducibility and provides more reliable limits of detection than polydisperse gold nanoparticle colloids. 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.

Clean surface and reactant‑free matrix

Morphology: spherical gold nanoparticles, no other shapes. 

Matrix: reactant‑free aqueous colloidal suspension, low ionic strength.

The reactant‑free and stabilizer-free formulation minimizes interference with surface functionalization and reduces aggregation risk, helping maintain colloidal stability, signal intensity, and assay robustness over time. Find out Why should Stabilizing agents be Avoided.

Surface options for flexible conjugation

- Citrate: for passive adsorption of antibodies and proteins, ideal for rapid screening and conjugation optimization.

- PEG5000‑carboxylate (thiol‑PEG‑COOH): for covalent EDC/NHS coupling to amine‑containing biomolecules, with reduced non‑specific binding and enhanced stability in complex matrices.

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.

Optimized OD for biosensing

Optical density options: OD 20 and OD 50. These concentrations are tuned for robust conjugation performance and reliable signal generation in common biosensing formats. 

IVD‑oriented quality control and CoA

Each lot includes a detailed CoA with lot‑specific TEM images, size distribution, UV‑Vis spectra, hydrodynamic diameter, PdI, zeta potential, and key QC parameters, supporting internal QC, method validation, and regulatory submissions for IVD and medical diagnostic products. 

Consult a typical CoA for 40nm Gold Nano-Spheres, PEG5K-CARB, OD=50 and CoA for 40nm Gold Nano-Spheres, Citrate, OD=20.

When to choose 40 nm

The 40 nm IVD‑READY Gold Nanoparticles format is ideal for IVD assays that require a balance of strong signal, low background, and highly controlled bioconjugation. It is particularly suited for quantitative LFAs, ELISA‑type colorimetric tests, and IVD biosensors where precise antibody orientation and reproducible analytical performance are critical. Choose 40 nm IVD‑READY Gold Nanoparticles when you need high‑quality optical response with cleaner backgrounds than larger particles and greater per‑particle signal than smaller diameters, using this size as a versatile mid‑range benchmark during IVD biosensing assay optimization. Learn more about Gold Nanoparticles in Biosensing and Personalized Medicine.

Customization and OEM Options

Custom diameters, optical densities, and PEG spacer lengths are available on request. Contact us to discuss your specific requirements.

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.

Browse more sizes in IVD-READY Collection.

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