文摘
Multicomponent ligand interactions are involved in essentially all practical nanoparticle (NP) applications. Presented herein is the finding that multicomponent ligand binding to gold nanoparticles (AuNPs) can be highly dependent on the sequence of ligand mixing with AuNPs. Quantitative study revealed that the competitive adenine and glutathione (GSH) adsorption onto both as-synthesized and pegylated AuNPs is predominantly kinetically controlled, and adenine that binds only nonspecifically to AuNP adsorbs faster than GSH. This raises concerns about the validity of the popular practice in current NP research of using the Langmuir isotherm or its variants to model multicomponent ligand adsorption on NPs. Mechanistically, this sequence dependency is due to the fact that there is no spontaneous ligand desorption even for the model protein and small molecules that can bind only nonspecifically to AuNPs. The insights and experimental methods provided in this work should be important for molecular-level understanding of nanoparticle interfacial interactions.