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Gold Nanoparticle Conjugation Services

Custom AuNP bioconjugation for oligonucleotides, antibodies, proteins, peptides, aptamers, small molecules, and diagnostic assay development using optimized nanoparticle size, surface chemistry, purification, and characterization.

AuNP bioconjugation oligo-gold conjugates antibody-gold conjugates lateral flow assays UV-Vis QC

Overview

Gold nanoparticle conjugation is a nanomaterial-based bioconjugation approach used to attach biomolecules and functional ligands to nanoscale gold surfaces. Gold nanoparticles are valued for their strong colorimetric signal, surface plasmon resonance, high surface-to-volume ratio, and compatibility with multiple surface chemistries.

Bio-Synthesis provides custom gold nanoparticle conjugation services for research, diagnostic, biosensor, labeling, and lateral flow assay applications. We help select the appropriate AuNP size, linker chemistry, biomolecule format, purification strategy, and characterization workflow based on your intended use.

Why Choose Gold Nanoparticle Bioconjugation?

Strong Optical Signal

AuNPs provide intense visible color and plasmon-based signal for colorimetric assays and detection systems.

Flexible Chemistry

Thiol-gold, passive adsorption, EDC/NHS, maleimide, biotin-streptavidin, and PEGylated surfaces can be used.

Tunable Particle Size

Particle diameter can be selected to balance loading capacity, signal intensity, stability, and assay performance.

Assay Development

Useful for lateral flow assays, biosensors, molecular diagnostics, imaging, and probe development.

Key advantage: gold nanoparticles combine nanoscale surface functionalization with strong optical readout, making them especially useful for rapid diagnostics, biosensors, and visible detection platforms.

Gold Nanoparticle Bioconjugation Platform

Gold nanoparticles can be functionalized with oligonucleotides, antibodies, proteins, peptides, aptamers, PEG chains, dyes, small molecules, and targeting ligands. Surface design controls stability, spacing, biological activity, and detection performance.

AuNP Surface Functionalization Thiolated oligos Antibodies Proteins PEG / linkers Peptides Aptamers / ligands AuNP
Gold nanoparticle conjugation platform showing biomolecule attachment, linker design, and surface stabilization.

Surface Attachment

Biomolecules can be coupled through thiol-gold binding, covalent linkers, adsorption, affinity systems, or functionalized coatings.

Stability Design

Buffer, salt, pH, ligand density, PEG spacing, and purification are optimized to reduce aggregation and preserve activity.

Assay Performance

Particle size and surface loading influence visual signal, kinetics, nonspecific binding, and detection sensitivity.

What Can Be Conjugated to Gold Nanoparticles?

Oligonucleotides

DNA, RNA, thiol-modified oligos, amine-modified oligos, aptamers, probes, and modified nucleic acids.

Explore oligo-gold conjugation

Antibodies & Fragments

Monoclonal antibodies, polyclonal antibodies, Fab, scFv, nanobodies, and capture or detection antibodies.

Explore antibody-gold conjugation

Proteins & Enzymes

Recombinant proteins, enzymes, carrier proteins, streptavidin, avidin, and protein biomarkers.

Explore protein-gold conjugation

Peptides

Thiolated peptides, cysteine-containing peptides, targeting peptides, cell-penetrating peptides, and peptide probes.

Explore peptide-gold conjugation

Small Molecules & Ligands

Biotin, haptens, drugs, dyes, fluorophores, chelators, affinity tags, and targeting ligands.

Explore ligand-gold conjugation

PEG & Surface Modifiers

PEGylation, spacer arms, charged coatings, carboxyl, amine, maleimide, and mixed monolayer designs.

Explore PEGylated AuNPs

Gold Nanoparticle Conjugation Chemistries

Thiol-Gold Conjugation

Direct attachment of thiol-modified oligonucleotides, peptides, PEG, or ligands through strong Au-S surface interactions.

Passive Adsorption

Common for antibodies and proteins using optimized pH, ionic strength, and stabilizers to preserve binding activity.

EDC/NHS Coupling

Carboxyl-functionalized AuNPs can be activated for amide bond formation with amine-containing biomolecules.

Maleimide-Thiol Coupling

Maleimide-functionalized particles enable selective coupling to cysteine-containing peptides, proteins, or antibody fragments.

Biotin-Streptavidin Systems

Biotinylated biomolecules can be immobilized using streptavidin- or avidin-functionalized AuNP platforms.

PEGylated Mixed Monolayers

PEG spacers and passivating ligands can improve colloidal stability, reduce nonspecific binding, and control ligand spacing.

Gold Nanoparticle Size Selection Guide

Particle size affects optical signal, surface area, biomolecule loading, steric accessibility, colloidal stability, and assay sensitivity. The guide below provides practical starting points for selecting AuNP diameter.

Practical selection rule: choose the smallest particle that provides enough optical signal and surface loading for your application while maintaining colloidal stability and biomolecule activity. As a common starting point, 20-40 nm AuNPs are often selected for antibody-based lateral flow assays, while 5-20 nm AuNPs are commonly used for oligonucleotide and aptamer conjugates.

Particle Size by Application

Particle SizeTypical Use CasesSuitable BiomoleculesKey Advantages
5-10 nm High-density functionalization, intracellular studies, compact probes Oligonucleotides, aptamers, peptides, small ligands Small footprint, high curvature, useful for dense surface display
10-20 nm Molecular diagnostics, probe development, nucleic acid systems DNA/RNA, aptamers, small proteins, peptides Good balance of stability, loading, and nanoscale size
20-40 nm Lateral flow assays, colorimetric detection, standard diagnostics Antibodies, proteins, oligos, aptamers Strong red color, robust optical signal, widely used assay range
40-60 nm Enhanced sensitivity assays, visible labeling, stronger signal formats Antibodies, enzymes, larger proteins Higher optical intensity and increased surface area
60-100 nm Imaging, high-sensitivity detection, larger biomolecule display Antibodies, large proteins, multivalent constructs Very strong plasmon signal and higher loading capacity
>100 nm Specialized aggregation-based sensing or strong visual signal applications Large biomolecules, complexes, surface coatings Maximum visual signal, but lower colloidal stability and slower diffusion

Recommended Particle Size by Biomolecule Type

Biomolecule TypeRecommended AuNP SizePreferred Attachment StrategyDesign Rationale
DNA / RNA oligonucleotides 5-20 nm Thiol-gold, spacer-modified oligos, mixed PEG monolayers Supports dense loading and controlled spacing while preserving hybridization.
Aptamers 10-30 nm Thiol-gold, biotin-streptavidin, spacer/linker strategies Allows folding and target binding while maintaining useful optical signal.
Peptides 5-20 nm Cysteine/thiol-gold, maleimide-thiol, linker-mediated coupling Small biomolecules benefit from high curvature and dense surface display.
Antibodies 20-40 nm Passive adsorption, oriented coupling, carboxyl/amine linker chemistry Balances signal strength, surface area, and compatibility with lateral flow formats.
Antibody fragments 10-30 nm Thiol-maleimide, site-directed coupling, affinity-mediated orientation Smaller fragments can use smaller particles while reducing steric hindrance.
Proteins and enzymes 20-60 nm Passive adsorption, EDC/NHS, affinity tags, PEG spacers Provides sufficient surface area while helping preserve folded structure and activity.
Small molecules / haptens 10-40 nm Linker-mediated coupling, thiol-gold, biotin-streptavidin Linker length and spacing often determine recognition and assay performance.
  • Smaller particles support better diffusion and compact probe design.
  • Mid-size particles provide strong colorimetric signal and good colloidal stability.
  • Larger particles increase visual signal but may increase aggregation risk.
  • Surface density, linker length, buffer, salt, and PEG spacing should be optimized with particle size.

Applications of Gold Nanoparticle Conjugates

Lateral Flow Assays

Antibody-gold and protein-gold conjugates for rapid diagnostic strip development and visible readout.

Colorimetric Detection

AuNP aggregation, plasmon shift, and signal amplification formats for molecular and immunoassays.

Molecular Diagnostics

Oligonucleotide- and aptamer-functionalized AuNPs for hybridization, target recognition, and nucleic acid detection.

Biosensors

Functionalized AuNPs for electrochemical, optical, SPR, and affinity-based biosensor platforms.

Imaging and Labeling

Gold conjugates for microscopy, electron-dense labeling, cellular studies, and probe development.

Targeted Delivery Research

Ligand-, peptide-, aptamer-, or antibody-modified AuNPs for targeted binding and delivery studies.

Quality Control & Characterization

UV-Vis Spectroscopy

Surface plasmon peak position and broadening are monitored to evaluate conjugation and aggregation.

Particle Size Assessment

Hydrodynamic size and size distribution can be evaluated to confirm colloidal stability after conjugation.

Purification

Unbound biomolecule and excess reagents are removed using an appropriate purification method for the particle and biomolecule.

Loading Evaluation

Conjugation efficiency, biomolecule loading, or depletion can be assessed depending on molecule type and assay needs.

Functional Testing

Binding, hybridization, enzymatic activity, or assay-specific testing can be performed upon request.

Stability Review

Buffer compatibility, salt tolerance, aggregation behavior, and storage conditions can be evaluated for downstream use.

Gold Nanoparticle Conjugation Keywords and Use Cases

This page covers custom gold nanoparticle conjugation, AuNP bioconjugation, oligonucleotide-gold conjugates, DNA-functionalized gold nanoparticles, antibody-gold nanoparticle conjugates, protein-AuNP conjugation, peptide-gold nanoparticle conjugation, PEGylated gold nanoparticles, lateral flow gold conjugates, biosensor nanoparticles, and diagnostic gold nanoparticle probes.

DNA-AuNP conjugates RNA-AuNP conjugates antibody gold colloid lateral flow gold conjugates gold nanoparticle biosensors Au-S conjugation EDC/NHS AuNP coupling

FAQ

Can you conjugate oligonucleotides to gold nanoparticles?
Yes. Thiol-modified DNA or RNA oligonucleotides are commonly conjugated to gold nanoparticles through Au-S surface chemistry.
Is gold nanoparticle conjugation a type of nanomaterial conjugation?
Yes. Gold nanoparticles are nanoscale materials, so attaching biomolecules to AuNP surfaces is considered nanomaterial-based bioconjugation.
What size gold nanoparticle should I use?
The best size depends on your biomolecule and assay. Oligonucleotides often use 5-20 nm AuNPs, while antibody-based lateral flow assays commonly use 20-40 nm AuNPs.
Can you conjugate antibodies to gold nanoparticles?
Yes. Antibodies can be adsorbed or covalently attached depending on required orientation, stability, and assay performance.
How do you confirm conjugation?
Typical characterization includes UV-Vis spectroscopy, particle size or aggregation assessment, purification review, and molecule-specific loading or functional testing when applicable.
Can you help optimize a lateral flow gold conjugate?
Yes. Particle size, antibody loading, buffer, blocking, salt tolerance, pH, and stability can be optimized for lateral flow assay development.

Contact & Quote Request

or the fastest review, send your biomolecule type, available functional groups, desired AuNP size, application, required quantity, buffer limitations, purity needs, and any assay performance requirements.

Fast quote checklist

  • Biomolecule: oligo, aptamer, antibody, protein, peptide, ligand, dye, or PEG
  • Available handles: thiol, amine, carboxyl, biotin, maleimide, azide, alkyne, or custom
  • Preferred AuNP size or application-based size recommendation
  • Desired conjugation chemistry, loading level, and purification needs
  • Application: lateral flow, biosensor, imaging, colorimetric assay, diagnostics, or research

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