Synthesis of methacrylated hyaluronic acid with tailored degree of substitution
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- 作者：Marion H.M. Oudshoorn ; Robert Rissmann ; Joke A. Bouwstra ; Wim E. Hennink
- 关键词：Hyaluronic acid ; Methacrylation ; Hydrogels
- 刊名：Polymer
- 出版年：2007
- 出版时间：23 March 2007
- 年：2007
- 卷：48
- 期：7
- 页码：1915-1920
- 全文大小：230 K
文摘
The aim of this work was to develop a new method to derivatize hyaluronic acid (HyA) with polymerizable methacrylate residues with precise control over the substitution degree. The synthesis of methacrylated HyA (HyA-MA) was performed in dimethyl sulfoxide (DMSO) using glycidyl methacrylate (GMA) and 4-(N,N-dimethylamino)pyridine as a catalyst. HyA was rendered soluble in DMSO by exchanging the Na+ ions by the more lipophilic tetrabutylammonium ions. HyA-MA with a fully controlled degree of substitution (DS, defined as the number of methacrylate groups per 100 disaccharide units), ranging from 5 to 30, was obtained at 50 °C after 48 h. Hydrogels were obtained upon radical polymerization of aqueous solutions of HyA-MA using potassium peroxodisulfate (KPS) as initiator and N,N,N′,N′-tetramethylethylenediamine (TEMED) as catalyst. Almost complete methacrylate conversion (95 % ) was achieved for hydrogels obtained by polymerization of HyA-MA with a degree of substitution of 15. At lower DS (DS 8.5 and 5) the methacrylate conversion was 82 % and 68 % , respectively. Rheological characterization showed that with increasing DS the storage modulus of these HyA-MA hydrogels increased. Swelling experiments showed that HyA-MA gels with a DS of 15 or above were dimensionally stable, whereas HyA-MA gels with DS 5 and DS 8.5 swelled 1.6 and 1.4 times their initial weight, respectively. In conclusion, this paper shows that the DS of HyA-MA can be tailored by the reaction conditions and that consequently HyA-MA hydrogels with different characteristics can be prepared.