Lidia M. Vallarino
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Professor |
Education
Ph.D., University of Milano, Italy
Research interests
Three related projects are under investigation:
Europium and terbium macrocycles for use as luminescent stains.
To be effective as a luminescent stain in cytology or immunology, a compound must be: 1) water soluble, 2) stable or inert under the conditions of use and 3) intensely luminescent. In addition, it must contain functional groups suitable for coupling to biological substrates. The use of the europium(III) and terbium(III) ions in luminescent stains is based on the fact that some of their complexes emit a number of nearly monochromatic radiations in the visible region when exposed to ultraviolet light. This long-lived luminescence is especially suitable for biological staining because it can be easily distinguished from the intrinsic fluorescence of the substrate. Previous work has shown that macrocyclic complexes of the type illustrated in I are both water- soluble and extremely inert to metal release in solution. Furthermore, their luminescence can be “switched on” as required by the addition of certain chelating counterions.
Current efforts are directed at the synthesis and characterization of backbone functionalized macrocycles and to the development of procedures for their attachment to avidin, streptavidin and other immunological substrates.
Paramagnetic reagents for nuclear magnetic resonance spectroscopy
X-ray crystallographic studies have shown that in the lanthanide complexes illustrated in I the anions and/or solvent molecules are coordinated to the metal ion on opposite sides of the macrocycle. In solution the metal-macrocycle entity is inert and retains its identity, whereas the exo-cyclic ligands are labile and rapidly equilibrate with the environment. Accordingly, the macrocyclic complexes of certain paramagnetic lanthanides can serve as “shift reagents” in nuclear magnetic resonance spectroscopy, and those of gadolinium(III) can act as contrast agent for in vivo magnetic resonance imaging. The properties and applications of these complexes are currently under study.
Synthesis and characterization of polymers containing heavy metal ions
The incorporation of metal ions into an organic polymer may result in new materials that possess the desirable characteristics of both the inorganic and the organic components. For example, polymers containing the highly paramagnetic dysprosium(III), holmium(III) and erbium(III) ions may be useful for magnetic shielding; polymers containing cerium(III) may offer protection from high-energy radiation, and polymers containing lead(II), cadmium(II) or mercury(II) may act as antifouling agents for marine structures. Current efforts involve the synthesis, structural characterization and model reactions of à,þ-difunctionalized metal-macrocycles suitable as co-monomers for metal-containing polyesters, polyurethanes and polyamides. Future work will study the conditions required to achieve polymer formation, as well as the structure and propertie09/15/2006ontents">Publications
- R.C. Leif, M.C. Becker, A. Bromm, Jr., L.M. Vallarino and S. Yang, “Fluorescence Resonance Energy Transfer Enhanced Luminescence (FRETEL) of Quantum Dyes®” in Ultrasensitive and Single-Molecular Detection Technologies, eds. G.J. Enderlein and Z.K. Gryczynski, SPIE Proceedings, 6092 (2006) 29-41.
- R. C. Leif and L. M. Vallarino, “Rare-earth Chelates as Fluorescent Markers in Cell Separation and Analysis,” in Cell Separation Science and Technology, ACS Symposium Series 46A, D. S. Kompala and P. Todd, Eds., American Chemical Society, Washington, DC, 1991, Chapter 3, p. 42-58.
- F. Benetollo, G. Bombieri, K. K. Fonda, A. Polo, J. R. Quagliano, and L. M. Vallarino, “Complexes of the Lanthanide(III) Ions with an Aromatic Six-Nitrogen-Donor Macrocyclic Ligand,” Inorg. Chem., 30, 1345 (1991).
- F. Benetollo, G. Bombieri, K. K. Fonda, and L. M. Vallarino, “Crystal Structure and Nuclear Magnetic Resonance Spectra of Macrocyclic Complexes of the Nd(III) and Eu(III) Ions,” Polyhedron, 9, 1411 (1990).
