[Zurück]

D. Ret, C. Siedler, S. Knaus:
"Cystamine modified glucuronic acid - an efficient tool to solve the problem of a correct DS determination of crosslinkable thiolated polysaccharides";
Vortrag: European Polymer Congress 2019 (EPF 2019), Crete, Greece; 09.06.2019 - 14.06.2019; in: "European Polymer Congress 2019 (EPF 2019)", (2019), S. 239.

Recently polysaccharides such as hyaluronan, alginate or pectin modified with cystamine rise in interest due to the high biocompatibility of the resulting hydrogels and the possibility to prepare very pure derivatives for pharmaceutical and tissue engineering purposes [1]. When reduced to the thiol form (Fig.1,A) the biopolymer chains are free to move and when reoxidized a stable network crosslinked by disulfide bonds is formed (Fig.1,B).


Fig. 1: Condition-dependent behaviour of thiolated polysaccharides

Control and accurate determination of the degree of substitution (DS) are of primary importance to produce materials with defined properties and to establish reliable structure-property-relationships. In literature characterization of such polymers by NMR spectroscopy, which is an effective and widespread method for DS determination, is very controversial and many different spectra are presented with different forms and positions of the signals necessary for quantitative analysis. In this study a way to master the challenge of a correct DS determination of crosslinkable thiolated polysaccharides by use of a novel model compound (Fig.2) and by using suitable measuring conditions is presented.



Fig.2: Structure of the novel model compound

The synthesis of GA-SS-GA and it´s stability under different conditions is described and it is shown that even the DS of high molar mass hyaluronan, where the proton mobility plays a crucial role [2], can be determined correctly by 1H NMR spectroscopy.

polysaccharides, hyaluronan, alginate or pectin modified with cystamine, high biocompatibility of the resulting hydrogels, pharmaceutical and tissue engineering purposes, biopolymer chains, reoxidized a stable network crosslinked by disulfide bonds