Novos macrociclos de lantanÃdeos: marcadores fotÃnicos projetados para aplicaÃÃes biotecnolÃgicas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The present work describes the synthesis, characterization and photophysical properties of the lanthanide cryptates [Ln⊂(bipy)2py(CO2Et)2]3+ and [Ln⊂(bipy)2py(CONHCH2CH2NH2)2]3+ with Ln3+ = Eu3+, Tb3+ and Gd3+, which are efficient light conversor molecular devices in aqueous solution. Emission spectroscopic analysis and lifetime measurements at 298K and 77K of such cryptates provided information about the position and characteristics of the ligand energy levels and lanthanide ions emission levels. A more efficient energy transfer was observed between the ligand triplet and emission level for the Terbium systems (T→5D4), with improvement on the cryptates emission quantum yield in aqueous solution. In the cryptate Tb⊂(bipy)2py(CO2Et)2 3+ 25% of quantum yield was found while the Europium analogue gave 14%. The cryptates [Ln⊂(bipy)2py(CONHCH2CH2NH2)2]3+with the lanthanides Eu3+ and Tb3+ were conjugated to Con A lectin and spectroscopically characterized. With the help of circular dichroism technique was elucidated that the secondary structure of Con A was maintained. Fluorescence and phosphorescence measurements of such protein complexes provided indications of its tertiary structure integrity and were also used for evaluating the degree of the cryptate conjugation. The Con A-cryptate system was applied in histochemical assays, where the cryptate worked as a luminescence marker for the detection of a breast tumor. The cryptate [Tb⊂(bipy)2py(CO2Et)2]3+ was conjugated to the LR-microcystin (a toxin produced by blue seaweed) for the development of a new LR-microcystin detection method in water samples

ASSUNTO(S)

macrociclos de lantanÃdeos quimica marcadores fotÃnicos aplicaÃÃes biotecnolÃgicas

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