FLUORESCENCE BEHAVIOR OF PYRENE UNDER POLARITY CHANGES OF ITS MICROENVIRONMENT IN THE PRESENCE OF CTAB AGGREGATES

HERMET, M.; BERNIK, D.; MORCELLE, S.R.; BAKÁS, L.

Santos

Congreso; XLII Congress of the Brazilian Biophysics Society; 2017

Brazilian Biophysics Society

The synthesis and purification of new surfactants devoted to pharmaceutical technology or to molecular biology studies is costly in time and resources as well as the biochemical assays to prove their efficacy in the task they are obtained for. In many cases proficiency at very low amounts are required. The efficiency of a given surfactant molecule depends on a series of factors among which critical micelle concentration (CMC) and the structure of the obtained micelles are crucial. CMC values at the submillimolar range are often observed for surfactants with bulky head-groups and long hydrophobic tails. A fast, easy and reliable methodology to find out the CMC of new surfactants is needed. Steady state fluorescent measurements are affordable in most of research laboratories, and many fluorescent molecular probes can afford this task. In this work we describe results obtained with the well-known pyrene probe and the surfactant CTAB (also known as cetrimide). CTAB was chosen given its net positive charge and its polar head not too voluminous, having some structural similarities with novel arginine-based cationic surfactants synthesized in our group by means of a biocatalytic strategy [1,2]. New information was obtained and the quality of the data acquired with different equipment is compared. In the course of data analysis, some of the assumptions inherent to pyrene photochemistry in its interaction with surfactants are reasserted, and some others are open to a broader perspective.