Efficient Phosphodiester Cleaving Nanozymes Resulting from Multivalency and Local Medium Polarity Control

The self-organization of Zn­(II) complexes on the surface of 1.6-nm diameter gold nanoparticles (nanozymes) allows the spontaneous formation of multiple bimetallic catalytic sites capable to promote the cleavage of a RNA model substrate. We show that by tuning the structure of the nanoparticle-coating monolayer, it is possible to decrease the polarity of the reaction site, and this in turn generates remarkable increments of the cleavage efficiency

Self-Assembly of a Catalytic Multivalent Peptide–Nanoparticle Complex

Catalytically active peptide–nanoparticle complexes were obtained by assembling small peptide sequences on the surface of cationic self-assembled monolayers on gold nanoparticles. When bound to the surface, the peptides accelerate the transesterification of the <i>p</i>-nitrophenyl ester of <i>N</i>-carboxybenzylphenylalanine by more than 2 orders of magnitude. The gold nanoparticle serves as a multivalent scaffold for bringing the catalyst and substrate into close proximity but also creates a local microenvironment that further enhances the catalysis. The supramolecular nature of the ensemble permits the catalytic activity of the system to be modulated in situ

Light-Triggered Thiol-Exchange on Gold Nanoparticles at Low Micromolar Concentrations in Water

The place-exchange reaction of thiol-containing peptides in a cationic monolayer on gold nanoparticles occurs very rapidly at low micromolar concentrations in water with excellent control over the degree of substitution. The driving force for this process is the binding of anionic peptides to a cationic monolayer surface which causes a strong increase in the local concentration of thiols. The place-exchange reaction can be triggered by light using a photolabile protecting group on the thiol moiety

Lanthanide-Based NMR: A Tool To Investigate Component Distribution in Mixed-Monolayer-Protected Nanoparticles

Gd³⁺ ions, once bound to the monolayer of organic molecules coating the surface of gold nanoparticles, produce a paramagnetic relaxation enhancement (PRE) that broadens and eventually cancels the signals of the nuclear spins located nearby (within 1.6 nm distance). In the case of nanoparticles coated with mixed monolayers, the signals arising from the different coating molecules experience different PRE, depending on their distance from the binding site. As a consequence, observation of the signal broadening patterns provides direct information on the monolayer organization