Nanoscale Surface Curvature Effects on Ligand–Nanoparticle Interactions: A Plasmon-Enhanced Spectroscopic Study of Thiolated Ligand Adsorption, Desorption, and Exchange on Gold Nanoparticles

Abstract

The interfacial adsorption, desorption, and exchange behaviors of thiolated ligands on nanotextured Au nanoparticle surfaces exhibit phenomenal site-to-site variations essentially dictated by the local surface curvatures, resulting in heterogeneous thermodynamic and kinetic profiles remarkably more sophisticated than those associated with the self-assembly of organothiol ligand monolayers on atomically flat Au surfaces. Here we use plasmon-enhanced Raman scattering as a spectroscopic tool combining time-resolving and molecular fingerprinting capabilities to quantitatively correlate the ligand dynamics with detailed molecular structures in real time under a diverse set of ligand adsorption, desorption, and exchange conditions at both equilibrium and nonequilibrium states, which enables us to delineate the effects of nanoscale surface curvature on the binding affinity, cooperativity, structural ordering, and the adsorption/desorption/exchange kinetics of organothiol ligands on colloidal Au nanoparticles. This work provides mechanistic insights on the key thermodynamic, kinetic, and geometric factors underpinning the surface curvature-dependent interfacial ligand behaviors, which serve as a central knowledge framework guiding the site-selective incorporation of desired surface functionalities into individual metallic nanoparticles for specific applications.

Monitoring the Dynamic Process of Formation of Plasmonic Molecular Junctions during Single Nanoparticle Collisions

“…Very recently, it has been reported that single gold atom positional change in the plasmonic molecular junctions of the NPoM configuration can lead to the transient formation of a “picocavity,” which leads to a high SERS enhancement and makes single molecule changes observable in the SERS trajectories . Nanoscale surface curvature also plays important roles to promote such variations . Therefore, it is reasonable that single molecule fluctuations can be observed in these highly dynamic GNP/molecule/GNE junctions involving tens to hundreds molecules.…”

“…[43] Nanoscale surface curvature also plays important roles to promote such variations. [44] Therefore, it is reasonable that single molecule fluctuations can be observed in these highly dynamic GNP/molecule/GNE junctions involving tens to hundreds molecules.…”

Extra-Small Gold Nanospheres Decorated With a Thiol Functionalized Biodegradable and Biocompatible Linear Polyamidoamine as Nanovectors of Anticancer Molecules

“…Vertegel et al (2004) observed a greater loss of lysozyme conformation adsorbed onto larger silica nanoparticles under otherwise similar conditions. About the gold nanoparticles, the effects of curvature on ligand interaction remains a complicate issue (Villarreal et al, 2017). Villarreal et al (2017) CD spectroscopy method is commonly used to determine protein structure and its interaction with other molecules.…”

“…About the gold nanoparticles, the effects of curvature on ligand interaction remains a complicate issue (Villarreal et al, 2017). Villarreal et al (2017) CD spectroscopy method is commonly used to determine protein structure and its interaction with other molecules. CD spectroscopy confirmed the Trastuzumab conjugation to the gold nanoparticles (Figure 3D and Supplementary Figure S4), but also suggested a correlation between Trastuzumab-conjugated secondary structure maintenance and the particle hydrodynamic radius (R).…”

Use of anodic stripping voltammetry to study the size-selective electrophoretic deposition and aggregation-dependent oxidation of metal nanoparticles.

“…This defies the idea that local NP curvature is responsible for the shift in oxidation potential. 38 We show that the oxidation potential is actually more related to the total surface area-to-volume ratio (SA/V). These results also explain why previous papers did not observe a shift in oxidation potential for NPs below 40 nm.…”