Lanthanide energy transfer

Davies, GM., Pope, S.J.A., Adams, H., etal. (2005) Structural and photophysical properties of coordination networks combining [Ru(bipy)(CN)4 ] - anions and lanthanide(lll) cations rates of photoinduced Ru-to-lanthanide energy transfer and sensitized near-infrared luminescence. Inorganic Chemistry, 44, 4656. 

Wenscl, T. O., Chang. C.-H.. and Meares. C. F., 1985. Difhision enhanced lanthanide energy transfer study of DNAcbound co-balt(n0 bleomycins Comparisons of accessibiUQ and electrostatic potemial witfi DNA complexes of ethidiimi and acridine oiange, BiocherrUstry 24 3060 3069. 

As has been described in [ Basics of Lanthanide Photophysics , BiinzU, Eliseeva] and in [ Stable Luminescent Chelates and MacrocyclicCompounds , Mathis, Bazin], luminescent lanthanide complexes contain an antenna chromophore that serves to efficiently absorb excitation light and transfer this energy to the incorporated lanthanide ion that can then exhibit its photoluminescence. In this case, the overall luminescence quantum yield,, ot, is given by the product of the photosensitisation efficiency Tjsens, which gives the overall antenna-to-lanthanide energy transfer efficiency, and the intrinsic photoluminescence quantum yield of the lanthanide ion, [Pg.137]

Herrera JM, Pope SJA, Adams H, Faulkner S, Ward MD (2006) Structural and photophysical properties of coordination networks combining [Ru(bpym)(CN)4] or [ Ru(CN)4-2(p-bpym)] " anions (bpym=2, -bipyrimidine) with lanthanide(III) cations Sensitized near-infrared luminescence from Yb(III), Nd(III), and Er(III) following Ru-to-lanthanide energy transfer. Inorg Chem 45 3895-3904... 

Tamao K, Miyaura N (2002) Introduction to Cross-Coupling Reactions. 219 1-9 Tanaka M (2003) Homogeneous Catalysis for H-P Bond Addition Reactions. 232 25-54 Tanner PA (2004) Spectra, Energy Levels and Energy Transfer in High Symmetry Lanthanide Compounds. 241 167-278 ten Cate MGJ, see Crego-Calama M (2005) 249 in press ten Holte P,see Zwanenburg B (2001) 216 93-124 Thiem J,see Werschkun B (2001) 215 293-325... 

Self-assembly of functionalized carboxylate-core dendrons around Er +, Tb +, or Eu + ions leads to the formation of dendrimers [19]. Experiments carried out in toluene solution showed that UV excitation of the chromophoric groups contained in the branches caused the sensitized emission of the lanthanide ion, presumably by an energy transfer Forster mechanism. The much lower sensitization effect found for Eu + compared with Tb + was ascribed to a weaker spectral overlap, but it could be related to the fact that Eu + can quench the donor excited state by electron transfer [20]. 

The intramolecular distances measured at room temperature with the AEDANS FITC pair were similar in the Ca2Ei and E2V states [297]. Ca and lanthanides are expected to stabilize the Ej conformation of the Ca -ATPase, since they induce a similar crystal form of Ca -ATPase [119,157] and have similar effects on the tryptophan fluorescence [151] and on the trypsin sensitivity of Ca -ATPase [119,120]. It is also likely that the vanadate-stabilized E2V state is similar to the p2 P state stabilized by Pi [418]. Therefore the absence of significant difference in the resonance energy transfer distances between the two states implies that the structural differences between the two conformations at sites recorded by currently available probes, fall within the considerable error of resonance energy transfer measurements. Even if these distances would vary by as much as 5 A the difference between the two conformations could not be established reliably. 

Charbonniere LJ, Hildebrandt N, Ziessel RF, Lohmannsroben HG (2006) Lanthanides to quantum dots resonance energy transfer in time-resolved fluoro-immunoassays and luminescence microscopy. J Am Chem Soc 128 12800-12809... 

Figure 5 Triplet-mediated ligand-to-metal energy transfer in lanthanide complexes.

An alternative approach is that adopted by Horrocks and co-workers, where the aromatic residues in metal-binding proteins are used as sensitizers. Since the distance between the metal and the donor is effectively fixed, this provides a rigid scaffold for the experiment, and the absence of a directly conjugated pathway between the metals means that Forster (through space) energy transfer can be assumed. The r-6 distance-dependence of this means that the extent of sensitized emission from the lanthanide ion provides information on the spatial relationship between the metal-ion binding site (lanthanide ions often bind at Ca2+ sites) and nearby aromatic residues. 58-60... 

Selvin, P. R. (1996). Lanthanide-based resonance energy transfer. IEEE Journal of selected topics in quantum electronics Lasers Biol. 2, 1077-1087. 

Lanthanide chelates also can be used in FRET applications with other fluorescent probes and labels (Figure 9.51). In this application, the time-resolved (TR) nature of lanthanide luminescent measurements can be combined with the ability to tune the emission characteristics through energy transfer to an organic fluor (Comley, 2006). TR-FRET, as it is called, is a powerful method to develop rapid assays with low background fluorescence and high sensitivity, which can equal the detection capability of enzyme assays (Selvin, 2000). 

Figure 9.51 Time-resolved FRET assay systems involve energy transfer between the lanthanide chelate and an organic dye that are brought together as two labeled molecules bind to an analyte. In this illustration, an antibody labeled with a lanthanide chelate is used along with a Cy5-labeled antibody to detect a protein target in solution. Excitation of the lanthanide label results in energy transfer and excitation of the cyanine dye only if they are held within close enough proximity to allow efficient FRET to occur. Under these conditions, excitation of the lanthanide chelate results in cyanine dye emission, which will not occur if the labeled antibodies have not bound to a target.

---