Lucia Pasquato

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We report here the first example of peptide-functionalized gold nanoparticles hydrolytically active against carboxylate esters. The active units are constituted by His-Phe-OH terminating thiols. The confinement of the catalytic units in the monolayer covering the nanoparticles triggers a cooperative hydrolytic mechanism operative at pH < 7 in which a(More)
We describe here a simple assay that allows the visual detection of a protease. The method takes advantage of the high molar absorptivity of the plasmon band of gold colloids and is based on the color change of their solution when treated with dithiols. We used C- and N-terminal cysteinyl derivatives of a peptide substrate exploiting its selective(More)
EPR spectroscopy has been used to study the interaction of para-substituted benzyl hydroxyalkyl nitroxides with the monolayer of water-soluble protected gold cluster made by a short alkyl chain and a triethylene glycol monomethyl ether unit. The inclusion of nitroxide probes in the more hydrophobic environment of the monolayer gave rise to a reduction of(More)
Electron spin resonance (ESR) has emerged as a powerful spectroscopic technique to study the properties of metal nanoparticles (NPs) protected by a self-assembled monolayer (SAM) of organic molecules. This technique has been employed to explore the capacity of homoligand monolayers to bind to a hydrophobic probe or to "sense" the hydrophobicity of(More)
Aqueous solutions of Au colloids (12 +/- 4 nm size) when treated with a blend of mono- and dithiols aggregate forming stable clusters, as evidenced by the shift of their surface plasmon (SP) band from 512 to ca. 600 nm. The presence of carboxylate ester functions on the dithiol allows its cleavage by addition of a cleaving agent, such as hydrazine. The(More)
Self-assembled monolayers composed of a mixture of thiolate molecules, featuring hydrocarbon or perfluorocarbon chains (H- and F-chains) terminating with a short poly(oxoethylene) (PEG) moiety, are the most extreme example of surfactant immiscibility on gold nanoparticles reported so far. The phase segregation between H-chains and F-chains and the(More)