August 1, 2011.
Lanthanide containing materials are receiving increasing attention due to their wide range of potential applications including bioanalytical imaging, dye-sensitized solar cells, nano-biotechnology and catalysis. The unique spectroscopic properties (intense and sharp emission bands with high color purity and high quantum efficiency) of lanthanides make them strong candidates for use as bio-markers or selective detectors. The attractiveness of lanthanides as future imaging agents as well as recent interest in their potential use in biological media has increased the need to understand the behavior of lanthanides in the presence of other ions or in ionic media.
The complexity of the biological media and the diversity and variability of the ions present in it makes it important to be aware of any interactions between the lanthanide complexes and ions. The focus of this research is to add to the knowledge base on the absorption and emission behavior of various lanthanide complexes in the presence of a range of ionic media. This study is designed towards understanding the spectroscopic behavior of lanthanides in ionic environments.
For the first segment of the study, absorbance spectra for solutions of lanthanide (III) nitrates in de-ionized (DI) water, and in aqueous solutions of NaCl and MgCl2 were compared and contrasted. These were complemented by measurements of emission spectra. While the presence of ions did not produce distinguishable changes in the absorbance spectra, there were significant changes in the emission intensity and emission profile of those lanthanides tested.
The next step would be to measure the emission of lanthanide compounds in ionic liquids and to test a broader variety of lanthanide compounds in biological media. These results suggest that further study is warranted with consideration to the use of lanthanides as biomarkers. PNNL-SA-82039
Pacific Northwest National Laboratory (PNNL)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation.