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Spectroscopic Aspects of the Cationic Dye Basic Orange 21


  Zehavit Eizig[1]  ,  Dan Thomas Major[2]  ,  Harvey Lee Kasdan[3]  ,  Elena Afrimzon[1]  ,  Naomi Zurgil[1]  ,  Maria Sobolev[1]  ,  Mordechai Deutsch[1]  
 [1] The Biophysical Interdisciplinary Schottenstein Center for the Research and Technology of the Cellome, Physics Department, Bar Ilan University, Ramat-Gan, 5290002 ISRAEL
[2] Department of Chemistry and the Lise Meitner-Minerva Center of Computational Quantum Chemistry, Bar-Ilan University
[3] Harvey L Kasdan PhD LTD, Zerubavel 9/4 Jerusalem 9351100, Israel

Spectroscopic properties of cationic dye Basic Orange 21 (BO21) in solutions, in solids and within leukocytes were examined. Results obtained with solutions indicate that influence of variables like pH, viscosity, salt composition and various proteins on the absorption spectrum of BO21 is negligible. However, in the presence of heparin, a blue shift (484nm-465nm) is observed, which is attributed to aggregation of BO21 on the polyanion. However, when embedded in basophils, the absorption spectra of intracellular BO21 is extremely red shifted, with two peaks (at 505nm and 550nm), found to be attributed to BO21 and BO21-heparin complex respectively, which are intracellularly hosted in non-aqueous environments.