Nucleotide-directed syntheses of gold nanohybrid systems with structure-dependent optical features: Selective fluorescence sensing of Fe3+ ions

Ditta Ungor; Edit Csapó; Barbara Kismárton; Ádám Juhász; Imre Dékány

doi:10.1016/j.colsurfb.2017.04.013

Nucleotide-directed syntheses of gold nanohybrid systems with structure-dependent optical features: Selective fluorescence sensing of Fe³⁺ ions

Colloids Surf B Biointerfaces. 2017 Jul 1:155:135-141. doi: 10.1016/j.colsurfb.2017.04.013. Epub 2017 Apr 9.

Authors

Ditta Ungor¹, Edit Csapó², Barbara Kismárton¹, Ádám Juhász³, Imre Dékány⁴

Affiliations

¹ MTA-SZTE Supramolecular and Nanostructured Materials Research Group, Department of Medical Chemistry, Faculty of Medicine, University of Szeged, H-6720 Dóm square 8, Szeged, Hungary.
² MTA-SZTE Supramolecular and Nanostructured Materials Research Group, Department of Medical Chemistry, Faculty of Medicine, University of Szeged, H-6720 Dóm square 8, Szeged, Hungary; Department of Physical Chemistry and Materials Sciences, University of Szeged, H-6720, Aradi v.t.1, Szeged, Hungary. Electronic address: juhaszne.csapo.edit@med.u-szeged.hu.
³ MTA-SZTE Supramolecular and Nanostructured Materials Research Group, Department of Medical Chemistry, Faculty of Medicine, University of Szeged, H-6720 Dóm square 8, Szeged, Hungary; Department of Physical Chemistry and Materials Sciences, University of Szeged, H-6720, Aradi v.t.1, Szeged, Hungary.
⁴ MTA-SZTE Supramolecular and Nanostructured Materials Research Group, Department of Medical Chemistry, Faculty of Medicine, University of Szeged, H-6720 Dóm square 8, Szeged, Hungary. Electronic address: i.dekany@chem.u-szeged.hu.

PMID: 28419942
DOI: 10.1016/j.colsurfb.2017.04.013

Abstract

This study demonstrates a one-step synthesis for the preparation of both adenosine monophosphate (AMP)-stabilized colloidal gold nanoparticles (AMP-Au NPs) and fluorescent gold nanoclusters (AMP-Au NCs). The dominant role of AMP:AuCl₄^- molar ratios in the formation of diverse nanosized Au products was proved. The size, the structure and the unique structure-dependent optical properties of the NPs and NCs were determined based on the results of numerous spectroscopic (UV-vis, fluorescence, infrared, x-ray photoelectron), high resolution electron microscopy (HRTEM) and dynamic light scattering (DLS) techniques. Stabile AMP-Au NPs with diameter of ca. 11nm and ultra-small AMP-Au NCs having blue fluorescence (λ_em=480nm) were identified. In addition, the AMP-Au NCs have been utilized to develop a selective sensor for the detection of Fe³⁺ ions in aqueous medium based on fluorescence quenching. Several essential metal ions and anions have been tested but our results clearly supported that dominant quenching was observed only for Fe³⁺ ions. Based on the determined limit of detection (LOD=2.0μM) our system is capable of detecting Fe³⁺ ions in drinking water. The Stern-Volmer constants (K_SV) and various thermodynamic parameters (ΔG, ΔH°, ΔS°, ΔC_p) of the quenching process have also been determined by the Stern-Volmer fitting of the fluorescence data in order to better understand the quenching mechanism.

Keywords: Adenosine monophosphate; Biosensor; Fluorescence quenching; Gold nanoclusters; Gold nanoparticles; Iron ion.

MeSH terms

Adenosine Monophosphate / chemistry*
Biosensing Techniques*
Drinking Water / chemistry
Gold / chemistry*
Humans
Iron / analysis*
Kinetics
Limit of Detection
Metal Nanoparticles / chemistry*
Metal Nanoparticles / ultrastructure
Particle Size
Spectrometry, Fluorescence / methods*
Thermodynamics

Substances

Drinking Water
Adenosine Monophosphate
Gold
Iron