Journal of Nanoparticle Research

, Volume 13, Issue 12, pp 6455–6465 | Cite as

Synthesis, characterisation and functionalisation of luminescent silica nanoparticles

  • Jessica Labéguerie-Egéa
  • Helen M. McEvoy
  • Colette McDonagh
Research Paper


The synthesis of highly monodispersed, homogeneous and stable luminescent silica nanoparticles, synthesized using a process based on the Stöber method is reported here. These particles have been functionalised with the ruthenium and europium complexes: bis (2,2′-bipyridine)-(5-aminophenanthroline) Ru bis (hexafluorophosphate), abbreviated to (Ru(bpy)2(phen-5-NH2)(PF6)), and tris (dibenzoylmethane)-mono (5-aminophenanthroline) europium(III), abbreviated to (Eu:TDMAP). Both dyes have a free amino group available, facilitating the covalent conjugation of the dyes inside the silica matrix. Due to the covalent bond between the dyes and the silica, no dye leaching or nanoparticle diameter modification was observed. The generic and versatile nature of the synthesis process was demonstrated via the synthesis of both europium and ruthenium-functionalised nanoparticles. Following this, the main emphasis of the study was the characterisation of the luminescence of the ruthenium-functionalised silica nanoparticles, in particular, as a function of surface carboxyl or amino group functionalisation. It was demonstrated that the luminescence of the ruthenium dye is highly affected by the ionic environment at the surface of the nanoparticle, and that these effects can be counteracted by encapsulating the ruthenium-functionalised nanoparticles in a plain 15 nm silica layer. Moreover, the ruthenium-functionalised silica nanoparticles showed high relative brightness compared to the free dye in solution and efficient functionalisation with amino or carboxyl groups. Due to their ease of fabrication and attractive characteristics, the ruthenium-functionalised silica nanoparticles described here have the potential to be highly desirable fluorescent labels, particularly, for biological applications.


Silica Nanoparticles Luminescence Functionalisation Biomedical diagnostic Fluorescent labels Nanomedicine 



The authors would like to thank Tiina Toivonen from the Electron Microscopy Laboratory, University College Dublin for the TEM pictures and Dr. Martin Schulz and Professor Han Vos for useful discussions. This study was funded in party by the European Commission under the Seventh Framework Programme within the research project NANOMUBIOP (Enhanced sensitivity Nanotechnology-based Multiplexed Bioassay Platform for diagnostic applications).


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Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Jessica Labéguerie-Egéa
    • 1
  • Helen M. McEvoy
    • 1
  • Colette McDonagh
    • 1
  1. 1.Optical Sensors LaboratoryNational Centre for Sensor Research, Dublin City UniversityDublin 9Ireland

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