Nanoparticle‐Imprinted Matrices as Sensing Layers for Size‐Selective Recognition of Silver Nanoparticles

Abstract

AbstractThis study extends the concept of nanoparticle‐imprinted matrices (NAIMs) to systems in which template nanoparticles (NPs) are immobilized on a conducting surface and a polymer matrix is built around them before the release of the template NPs. Specifically, citrate‐stabilized AuNPs, 40 nm in diameter, were bound to a 3‐aminopropyltriethoxysilane (APTES)‐modified indium tin oxide (ITO) electrode at pH 5. Subsequently, a polymer matrix was generated by electropolymerization of a self‐inhibiting poly(phenol) (PPh) layer. The template AuNPs were removed either by electro‐oxidation of the Au core during linear sweep voltammetry (LSV) in Cl−‐containing aqueous solution or by chemical oxidation in aqueous KCN solution. After template removal, remaining nanocavities were found to be size‐selective in the competitive reuptake of analyte NPs, as demonstrated by the preference for citrate‐stabilized silver nanoparticles (AgNPs) with 20 nm diameter over AuNPs with 50 nm diameter. The remaining nanocavities and their size‐recognition ability were examined by scanning electron microscopy and LSV. Complementing studies by X‐ray photoelectron spectroscopy and scanning force microscopy corroborated the template embedding, template release, and analyte NP uptake.