Abstract

From fundamental and technological points of view, there is interest in developing opticaltransducers exploiting the localized surface plasmon resonance (LSPR) of gold nanoparticles(Au NPs) for the study of interaction of biomolecules as well as of their functionalizationmechanism of inorganic surfaces.Spectroscopic ellipsometry monitoring the LSPR change gives the possibility to detect withgood resolution and accuracy time-dependent changes of amplitude ?(t) and phase ?(t) [1]during the immobilization of biomolecules at the solid-liquid interfaces. The simultaneousmeasurements of kinetics of both ellipsometric parameters ?(?,t) and phase ?(?,t) enable toreach advanced sensitivity in a wide range of the binding process, even up to the completeformation of a biomolecular layer [2].One of the problems encountered in developing Au NPs LSPR sensor is the change of thesensor itself due to mobility of the Au NPs depending on the interaction with thefunctionalizing molecules.As an example in the case of the most investigatedthiols functionalization, depending on themolecular structure of the thiol and Au NPs size,interparticle aggregation may occur resulting ininstability of the sensor itself.The aim of this work is to demonstrate theadvantage of simultaneous measurements of ?(t)and ?(t) for the evaluation of the interaction ofbiomolecules with Au NPs inducing theiraggregation and temporal instability. Onceellipsometry has been useful to identify a stable AuNPs sensing substrate (in various conditions ofsolvents, pH, molecules, etc..), parameterscharacterizing the immobilization kinetics ofporphirins and antigen interaction withimmobilized antibodies is shown. Theellipsometric characterization is corroborated bymorphological analysis with atomic forcemicroscopy (AFM) also operating in electric forcemode (Kelvin probe) and by structural analysis ithRaman spectroscopy.

Autore Pugliese

• Bianco Giuseppe Valerio , Losurdo Maria , Giangregorio Maria Michela

Tutti gli autori

• M.M.Giangregorio; G.V.Bianco; P.Capezzuto G.Bruno; M.Losurdo

Titolo volume/Rivista

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Anno di pubblicazione

2013

ISSN

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ISBN

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Numero di citazioni Wos

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Settori ERC

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Codici ASJC

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