POLARIZED FEMROSECOND SPECTROSCOPY AS A TOOL FOR UNDERSTANDING OF THE MECHANISMS OF INTERCELLULAR REACTIONS

Abstract

Optical methods have undeniable advantages and are widely used nowadays for the study of biomolecules and biological samples with high spatial and temporal resolution. This allows to use the most advanced state-of-the-art physical methods for addressing the important problems of biology and medicine including diagnostics and treatment of many socially-important diseases. The lecture presents an overview of the latest achievements in this area obtained in the Ioffe Institute, St.Petersburg, Russia by means of polarized femtosecond spectroscopy. The endogenous coenzymes NADH and FAD play an important role in metabolic reactions in living cells, being actors and regulators of many redox reactions. The primary method for studying these fluorophores is observing their fluorescence after excitation with a short laser pulse. However, until very recently, the nature of the observed multi-exponential fluorescence decay remained controversial. In our recent studies the dynamics of excited states of NADH and FAD in various solutions were examined in detail and physical models were proposed that allowed to establish the mechanisms of the experimental observations. Along with fluorescence-based methods for studying biomolecules, pump-probe methods that offer significantly higher temporal resolution are attracting increasing attention. We have recently proposed and tested a new polarization-modulation pump-probe (POMO-PP) method that allowed to reduce dramatically the threshold of laser pulse energy needed for confident detection of molecular chromophores with sub-picosecond temporal resolution.
The study was carried out under the financial support of the Russian Science Foundation, grant # 26-75-31002.

Speaker

Oleg Vasyutinskii
Ioffe Institute, St.Petersburg
Russia

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