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Enzyme-mediated fast in situ formation of hydrogels from dextran–tyramine conjugates

Paper ID Volume ID Publish Year Pages File Format Full-Text
9985 657 2007 10 PDF Available
Title
Enzyme-mediated fast in situ formation of hydrogels from dextran–tyramine conjugates
Abstract

Dextran hydrogels were formed in situ by enzymatic crosslinking of dextran-tyramine conjugates and their mechanical, swelling and degradation properties were evaluated. Two types of dextran–tyramine conjugates (Mn,dextran=14 k, Mw/Mn=1.45), i.e. dextran–tyramine linked by a urethane bond (denoted as Dex–TA) or by an ester-containing diglycolic group (denoted as Dex–DG–TA), with different degrees of substitution (DS) were prepared. Hydrogels were rapidly formed under physiological conditions from Dex–TA DS 10 or 15 and Dex–DG–TA DS 10 at or above a concentration of 2.5 wt% in the presence of H2O2 and horseradish peroxidase (HRP). The gelation time ranged from 5 s to 9 min depending on the polymer concentration and HRP/TA and H2O2/TA ratios. Rheological analysis showed that these hydrogels are highly elastic. The storage modulus (G′), which varied from 3 to 41 kPa, increased with increasing polymer concentration, increasing HRP/TA ratio and decreasing H2O2/TA ratio. The swelling/degradation studies showed that under physiological conditions, Dex–TA hydrogels are rather stable with less than 25% loss of gel weight in 5 months, whereas Dex–DG–TA hydrogels are completely degraded within 4–10 d. These results demonstrate that enzymatic crosslinking is an efficient way to obtain fast in situ formation of hydrogels. These dextran-based hydrogels are promising for use as injectable systems for biomedical applications including tissue engineering and protein delivery.

Keywords
In situ forming; Hydrogel; Degradable; Enzymatic crosslinking; Dextran
First Page Preview
Enzyme-mediated fast in situ formation of hydrogels from dextran–tyramine conjugates
Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 28, Issue 18, 2007, Pages 2791–2800
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering