Long-wavelength emitting nanocrystals for bioassay applications

Valerie J. Leppert, Ashley S. Harvey, Geoff D. McCool, Forest T. Quinlan, Jun Feng, Guomin Shan, Pieter Stroeve, Subhash H. Risbud, Bruce D. Hammock, Ian M. Kennedy

Research output: Chapter in Book/Report/Conference proceedingConference contribution


New fluorophores that can be excited using visible or near-infrared radiation are of considerable interest for application in environmental and complex bioassays, where background fluorescence is exacerbated by ultra-violet or blue excitation. Useful labels for biomolecules include infrared emitting semiconductor nanoparticles that can be blue-shifted into the near-infrared and visible through quantum confinement effects, oxides of iron, and rare earth oxides. In this work, the synthesis of 6 nm average diameter lead selenide nanocrystals (well below the Bohr exciton diameter of 92 nm) through a reverse micelle technique; and the synthesis of iron and europium oxides with particles less than 5 nm in diameter by pulsed laser ablation is reported. The europium oxide nanoparticles' emission showed a large Stokes shift (144 nm or 216 nm. depending on excitation wavelength); a narrow, symmetric emission line at 610 nm (FWHM of 8 nm); and long lifetime (300 μs). The Eu 2O 3 nanoparticles. which were coated with silica for functionalization, displayed a greatly enhanced sensitivity over a conventional ELISA (0.025 ng ml -1 vs. 0.1 ng ml -1) when run in an atrazine immunoassay.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsG. Cao, W.P. Kirk
Number of pages12
StatePublished - 2002
EventNanoscale Optics and Applications - Seattle, WA, United States
Duration: Jul 8 2002Jul 9 2002


OtherNanoscale Optics and Applications
Country/TerritoryUnited States
CitySeattle, WA


  • Bioassay
  • Europium oxide
  • Iron oxide
  • Lead selenide
  • Nanocrystals
  • Near-infrared emitting
  • Quantum dots
  • Red emitting

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


Dive into the research topics of 'Long-wavelength emitting nanocrystals for bioassay applications'. Together they form a unique fingerprint.

Cite this