production of selected secondary metabolites in transformed ...

HYDROPHOBIZED SODIUM HYALURONATE IN AQUEOUS
SOLUTION - A FLUORESCENCE STUDY
Ing. Filip Mravec, 3 rd year PGS
Supervisor: doc. Ing. Miloslav Pekař, CSc.
Brno University of Technology, Faculty of Chemistry, Institute of Physical and Applied
Chemistry, Purkyňova 118, 612 00 Brno, e-mail: mravec@fch.vutbr.cz
INTRODUCTION
Polysaccharides and their derivatives have become as major components for the
development of biocompatible and biodegradable materials with many areas of interests (e.g.
tissue engineering, drug delivery). Chemical modification, which no affected
biodegradability, can lead to the expansions of medicine and engineering applications.
Hyaluronan is major component of pericellular and extracellurar matrices. It is a linear
polymer of the disaccharide D-glucuronic acid-1-β-3-N-acetylglukosamine (Figure 1a). It
plays important role in stabilizing the extracellular matrix in many tissues by binding to
specific proteins called hyaladherines. The main hyaluronan fraction is localized in skin
tissue.
The preparing of the hyaluronan derivatives are generally based on the esterifcation on the
D-glucuronic subunit. Our derivatives were modified on the second carbon on the glucuronic
subunit (Figure 1b). Because carboxylic groups are still free, we obtained the amphiphilic
polyelectrolyte - hydrophobized hyaluronan (hHA). From its structure we predict in aqueous
solution modified hyaluronan will aggregate to form micelle-like structures with non-polar
core. This aggregation behavior can be study by non-polar fluorescence probes solubilized to
H
H
O
O
HO
a
O
O
HO
b
O
O -
O -
O
OH
O
Na +
Na +
O
NH
R
HO
O
HO
O
C
H 3
C
H 3
Figure 1 Structure of the native hyaluronan (a) and its hydrophobized derivative (b),
R = C10.
this core.
Pyrene, benzo[d,e,f]fenanthrene is the even and alternating hydrocarbon (Figure 2a). The
“Pyrene I1:I3 ratio method” is widely used method to determine the critical aggregation
concentration (cac) for a lot of surfactant-based systems. Its unique response to the
Sborník soutěže Studentské tvůrčí činnosti Student 2006 a doktorské soutěže O cenu děkana 2005 a 2006
Sekce DSP 2006, strana 213
OH
OH
O
NH
O
O
NH
O
n
n
OH
OH