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Laboratoire d'Electrochimie Moleculaire, LEM, Paris

UMR CNRS - Université Paris Diderot - Paris France

Master Frontiers in Chemistry | UFR de Chimie - Université Paris Diderot - Paris 7 CNRS - Institut de chimie Université de Paris Master Chimie Sorbonne Paris Cité UFR de Chimie - Université Paris Diderot - Paris 7 CNRS - Institut de chimie
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Université Paris Diderot
Université de Paris CNRS, Centre National de la Recherche Scientifique

Le LEM - Publications: Abstracts

Publication 724

ACS Nano , 7 (57), 4151-4163, 2013

Probing Individual Redox PEGylated Gold Nanoparticles by Electrochemical-Atomic Force Microscopy

Kai Huang, Agnès Anne, Mohamed Ali Bahri, and Christophe Demaille

Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'Electrochimie Moléculaire, Unité Mixte de Recherche Université–CNRS no. 7591, Bâtiment Lavoisier, 15 Rue Jean de Baïf, 75205 Paris Cedex 13, France

Electrochemical-Atomic Force microscopy (AFM-SECM) was used to simultaneously probe the physical and electrochemical properties of individual ~20 nm-sized gold nanoparticles functionalized by redox-labeled PEG chains. The redox PEGylated nanoparticles were assembled onto a gold electrode surface, forming a random nanoarray, and interrogated in situ by a combined AFM-SECM nanoelectrode probe. We show that, in this so called mediator-tethered (Mt) mode, AFM-SECM affords the nanometer-resolution required for resolving the position of individual nanoparticles, and measuring their size, while simultaneously electrochemically directly contacting the redox-PEG chains they bear. The dual measurement of the size and current response of single nanoparticles uniquely allows the statistical distribution in grafting density of PEG on the nanoparticles to be determined, and correlated to the nanoparticle diameter. Moreover, because of its high spatial resolution, Mt/AFM-SECM allows to “visualize” simultaneously but independently, the PEG corona and the gold core of individual nanoparticles. Beyond permitting the first demonstration of single nanoparticle resolution by an electrochemical microscopy technique, the results reported here also pave the way toward using Mt/AFM-SECM for imaging nano-objects bearing any kind of suitably redox labeled (bio)macromolecules.

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