Functionalized gold nanoparticles for 2-naphthol binding and their fluorescence properties

Andrea Majzik, Viktória Hornok, Noémi Varga, Réka Tabajdi, Imre Dékány

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Thiol-modified β-cyclodextrin functionalized gold nanoparticles (AuβCD NPs) were synthesized for binding 2-naphthol in aqueous solution. On the bases of the infrared spectroscopic results, the thiolated cyclodextrin molecules (βCD-(SH)2) are chemically bound to the gold nanoparticle surface. As a consequence of functionalization, a 3-dimensional hexagonal self-assembled structure developed in the dispersion, due to the interaction between the incorporated naphthol molecules. The red-shift of plasmon resonance maximum by 17nm in the UV-vis spectrum by the addition of 90μM 2-naphthol solution to the gold dispersion confirmed the adsorption of 2-naphthol in the βCD rings modified AuNPs. The in situ synthesis of AuNPs in the βCD solution resulted in fluorescent AuβCD system and the adsorption of 2-naphthol significantly modified the fluorescence properties. Upon excitation at λex=225nm, the emission peaks of 2-naphthol appearing at 360, 412 and 720nm are replaced by a peak at 400nm and by a second peak at 590-610nm depending on the AuβCD NP concentration. The quenching effect of AuNPs and βCD-(SH)2 molecules on the emission of 2-naphthol was evaluated based on the Stern-Volmer equation. The determined reaction free-enthalpy (δG=-25.44kJ/mol) data was similar to that of obtained from the microcalometric titration of 2-naphthol-βCD-(SH)2. The interaction of bulk or particular Au with naphthol was also examined in 2D system using surface plasmon resonance (SPR) method.

Original languageEnglish
Pages (from-to)244-251
Number of pages8
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume481
DOIs
Publication statusPublished - Sep 1 2015

Keywords

  • 2-Naphthol
  • Fluorescence quenching
  • Functionalization
  • Gold nanoparticles
  • β-Cyclodextrin

ASJC Scopus subject areas

  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

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