TY - JOUR
T1 - Water-soluble chitosan derivatives and pH-responsive hydrogels by selective C-6 oxidation mediated by TEMPO-laccase redox system
AU - Botelho da Silva, Suse
AU - Krolicka, Malgorzata
AU - van den Broek, Lambertus A.M.
AU - Frissen, August E.
AU - Boeriu, Carmen Gabriela
PY - 2018/4/15
Y1 - 2018/4/15
N2 - Chitosan is a polysaccharide with recognized antioxidant, antimicrobial and wound healing activities. However, this polymer is soluble only in dilute acidic solutions, which restricts much of its applications. A usual strategy for improving the functionality of polysaccharides is the selective oxidation mediated by 2,2,6,6-tetra-methyl-1-piperidinidyloxy (TEMPO) using laccase as a co-oxidant. In this work, the TEMPO-laccase redox system was used for the first time to selectively oxidize chitosan in order to produce tailored derivatives. The reaction was performed at pH 4.5 under continuous air supply and the oxidized products were characterized structurally and functionally. The TEMPO-laccase oxidation successfully added aldehyde and carboxylate groups to chitosan structure resulting in derivatives with oxidation between 4 and 7%. These derivatives showed increased solubility and decreased viscosity in solution. If chitosan is dissolved in diluted hydrochloric acid prior to TEMPO-laccase oxidation, a crosslinked chitosan derivative was produced, which was able to form a pH-responsive hydrogel.
AB - Chitosan is a polysaccharide with recognized antioxidant, antimicrobial and wound healing activities. However, this polymer is soluble only in dilute acidic solutions, which restricts much of its applications. A usual strategy for improving the functionality of polysaccharides is the selective oxidation mediated by 2,2,6,6-tetra-methyl-1-piperidinidyloxy (TEMPO) using laccase as a co-oxidant. In this work, the TEMPO-laccase redox system was used for the first time to selectively oxidize chitosan in order to produce tailored derivatives. The reaction was performed at pH 4.5 under continuous air supply and the oxidized products were characterized structurally and functionally. The TEMPO-laccase oxidation successfully added aldehyde and carboxylate groups to chitosan structure resulting in derivatives with oxidation between 4 and 7%. These derivatives showed increased solubility and decreased viscosity in solution. If chitosan is dissolved in diluted hydrochloric acid prior to TEMPO-laccase oxidation, a crosslinked chitosan derivative was produced, which was able to form a pH-responsive hydrogel.
KW - 2,2,6,6-Tetramethylpiperidinoxyl radical (TEMPO)
KW - Chitosan
KW - Laccase
KW - Oxidation
KW - pH-responsive hydrogel
KW - Soluble chitosan
U2 - 10.1016/j.carbpol.2018.01.050
DO - 10.1016/j.carbpol.2018.01.050
M3 - Article
AN - SCOPUS:85041505128
SN - 0144-8617
VL - 186
SP - 299
EP - 309
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
ER -