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Influence of the degree of acetylation on the enzymatic degradation and in vitro biological properties of trimethylated chitosans

Paper ID Volume ID Publish Year Pages File Format Full-Text
8521 596 2009 7 PDF Available
Title
Influence of the degree of acetylation on the enzymatic degradation and in vitro biological properties of trimethylated chitosans
Abstract

Chitosan derivatives such as N,N,N-trimethylated chitosan (TMC) are currently being investigated for the delivery of drugs, vaccines and genes. However, the influence of the extent of N-acetylation of these polymers on their enzymatic degradability and biological properties is unknown. In this study, TMCs with a degree of acetylation (DA) ranging from 11 to 55% were synthesized by using a three-step method. First, chitosan was partially re-acetylated using acetic anhydride followed by quantitative dimethylation using formaldehyde and sodium borohydrate. Then, in presence of an excess amount of iodomethane, TMC was synthesized. The TMCs obtained by this method showed neither detectable O-methylation nor loss in acetyl groups (1H NMR) and a slight increase in molecular weight (GPC) with increasing degree of substitution, implying that no chain scission occurred during synthesis. The extent of lysozyme-catalyzed degradation of TMC, and that of its precursors chitosan and dimethyl chitosan, was highly dependent on the DA and polymers with the highest DA showed the largest decrease in molecular weight. On Caco-2 cells, TMCs with a high DA (∼50%), a DQ of around 44% and with or without O-methylated groups, were not able to open tight junctions in the trans-epithelial electrical resistance (TEER) assay, in contrast with TMCs (both O-methylated and O-methyl free; concentration 2.5 mg/ml) with a similar DQ but a lower DA which were able to reduce the TEER with 30 and 70%, respectively. Additionally, TMCs with a high DA (∼50%) demonstrated no cell toxicity (MTT, LDH release) up to a concentration of 10 mg/ml.

Keywords
Trimethylated chitosan; Chitosan; MTT assay; Enzymatic degradation; TEER; Lysozyme
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Influence of the degree of acetylation on the enzymatic degradation and in vitro biological properties of trimethylated chitosans
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 30, Issue 18, June 2009, Pages 3129–3135
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us