Surface Chemistry of Gold Nanoparticles

Gold nanoparticles (AuNPs) exhibit remarkable optical, electronic and catalytic properties that are governed not only by core size and shape but critically by their surface chemistry. Monolayer ligands, often organised as self-assembled monolayers, stabilise colloidal suspensions, modulate interparticle interactions and serve as functional interfaces for targeted delivery, sensing and catalysis. Thiol–gold bonds remain the most prevalent anchor for small-molecule and polymeric ligands, enabling control over hydrophilicity, charge and steric protection. Mixed-ligand architectures and dynamic covalent exchange strategies allow post-synthetic tuning of solvent compatibility and surface reactivity without altering the metal core. Patterned monolayers—whether patchy, Janus or striped—introduce nanoscale domain structures that influence cellular uptake and protein adsorption in biomedical contexts. Characterisation techniques such as X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry probe chemical composition, while small-angle neutron scattering with deuteration reveals three-dimensional monolayer morphology under near-native conditions. The interplay between ligand organisation, monolayer dynamics and particle core properties underpins applications in photodynamic therapy, biosensing and heterogeneous catalysis. Recent advances in synthetic protocols and surface analysis are converging to deliver AuNPs as versatile nanoplatforms across disciplines, from environmental remediation to personalised nanomedicine.

Research from Nature Portfolio

Recent studies have employed contrast-variation small-angle neutron scattering to generate quantitative three-dimensional reconstructions of ligand shells on monodisperse gold nanoparticles. By selectively deuterating ligands or solvents, researchers have resolved mixed-ligand morphologies and tracked the evolution of shell structure under thermal annealing. This multiphase modelling approach has been extended to ternary ligand mixtures on gold, silver and copper cores, revealing characteristic length scales and domain distributions that correlate with simulations. These insights offer a robust framework for predicting how monolayer composition governs colloidal stability and interfacial behaviour, thereby informing the rational design of functionally tailored nanomaterials.

Surface Chemistry of Gold Nanoparticles publication trend

The graph below shows the total number of articles in surface chemistry of gold nanoparticles across all publications each year (not limited to Nature Index journals).

Technical terms

Ligand shell: The ensemble of molecules bound to the nanoparticle surface that defines interfacial properties and stability.

Self-assembled monolayer (SAM): An organised single layer of ligands chemisorbed on a surface, often via thiol–gold linkages.

Dynamic covalent exchange: A reversible chemical process that allows ligands on the nanoparticle surface to undergo bond formation and breakage under equilibrium conditions.

Small-angle neutron scattering (SANS): A technique to probe nanoscale structures in solution by analysing neutron scattering at low angles.

Plasmon resonance: The collective oscillation of conduction electrons in metallic nanoparticles, responsible for strong optical absorption and scattering.

X-ray photoelectron spectroscopy (XPS): A surface-sensitive analytical method for determining elemental composition and chemical states.

References

1. A General One-Step Synthesis of Alkanethiyl-Stabilized Gold Nanoparticles with Control over Core Size and Monolayer Functionality. Chemistry of Materials (2023).
2. Singlet Oxygen Generation Driven by Sulfide Ligand Exchange on Porphyrin–Gold Nanoparticle Conjugates. International Journal of Molecular Sciences (2023).
3. Gold nanoparticles with patterned surface monolayers for nanomedicine: current perspectives. European Biophysics Journal (2017).
4. Continuum tuning of nanoparticle interfacial properties by dynamic covalent exchange. Chemical Science (2018).
5. Quantitative 3D determination of self-assembled structures on nanoparticles using small angle neutron scattering. Nature Communications (2018).
6. XPS Examination of the Chemical Composition of PEGMUA‐Coated Gold Nanoparticles. Particle & Particle Systems Characterization (2022).