Metal-Enhanced Fluorescence Study in Aqueous Medium by Coupling Gold Nanoparticles and Fluorophores Using a Bilayer Vesicle Platform

Shweta Pawar, Anupam Bhattacharya, Amit Nag

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44 Scopus citations


Gold nanoparticles (AuNPs) display excellent plasmonic properties, which are expected to assist fluorescence enhancement for dyes, and the phenomenon is known as "metal-enhanced fluorescence" (MEF). In this study, we demonstrate AuNP-induced MEF for a modified bipyridine-based construct 4-(pyridine-2-yl)-3H-pyrrolo[2,3-c]quinoline (PPQ) when it binds with biologically important Zn 2+ . Importantly, this phenomenon is observed under aqueous conditions in a biocompatible bilayer vesicle platform. When PPQ binds with Zn 2+ to form the complex in the presence of appropriate AuNPs, MEF is evident once compared with the fluorescence intensity in the absence of AuNPs. Among the three different sizes of AuNPs used, the enhancement is observed with an average diameter of 33 nm, whereas 18 and 160 nm do not show any enhancement. A possible mechanism is ascribed to the radiating plasmons of the AuNPs, which can couple with the emission frequencies of the fluorophore under a critical distance-dependent arrangement. We witness that the enhancement in fluorescence is accompanied with a reduction in lifetime components. It is proposed that the mechanism may be predominantly derived from the enhancement of an intrinsic radiative decay rate and partly from the localized electric field effect. Overall, this work shows a rational approach to design fluorophore-metal configurations with the desired emissive properties and a basis for a useful nanophotonic technology under biological conditions.

Original languageEnglish
Pages (from-to)5983-5990
Number of pages8
JournalACS Omega
Issue number3
StatePublished - 31 Mar 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© Copyright 2019 American Chemical Society.


S.P. thanks the DST-inspire (IF150605) scheme for providing senior research fellowship. The authors gratefully acknowledge the support from the Department of Science and Technology, India, for the FIST grant SR/FST/CSI-240/2012. The Central Analytical Facility of BITS Pilani Hyderabad Campus is gratefully acknowledged for SEM and TCSPC experiments. The authors thank M. Dahiya, IISER Mohali, for help.

FundersFunder number
Department of Science and Technology, Government of Kerala


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