Regioselective fluorescent labeling of N,N,N-trimethyl chitosan via oxime formation

Berglind E. Benediktsdóttir; Kasper Kildegaard Sørensen; Mikkel Boas Thygesen; Knud Jørgen Jensen; Thórarinn Gudjónsson; Ólafur Baldursson; Már Másson

doi:10.1016/j.carbpol.2012.06.070

Regioselective fluorescent labeling of N,N,N-trimethyl chitosan via oxime formation

Berglind E. Benediktsdóttir, Kasper Kildegaard Sørensen, Mikkel Boas Thygesen, Knud Jørgen Jensen, Thórarinn Gudjónsson, Ólafur Baldursson, Már Másson

Department of Chemistry

17 Citations (Scopus)

Abstract

Fluorescent labeling of chitosan and its derivatives is widely used for in vitro visualization and is accomplished by random introduction of the fluorophore to the polymer backbone, conceivably altering the bioactivity of the polymer. Here, we report for the first time the regioselective conjugation of a fluorophore to the reducing end of a fully N,N,N-trimethylated chitosan (TMC) by oxime formation. End-labeled conjugation of 5-(2-((aminooxyacetyl)amino) ethylamino)naphthalene-1-sulfonic acid (EDANS-O-NH₂) fluorophore to TMC to form TMC-oxime-EDANS (f-TMC) was confirmed by ¹H NMR and fluorescence spectroscopy. Average molecular weight calculations of f-TMC with ¹H NMR and fluorescence spectroscopy gave similar results or ∼7.7 kDa. f-TMC in human bronchial epithelial cells was both cell membrane bound as well as intracellularly localized. This demonstrates the proof-of-concept for selective oxime formation at the reducing end of a chitosan derivative, which can be used for tracking chitosan in gene and drug delivery purposes and gives rise to further modifications with other functional groups.

Original language	English
Journal	Carbohydrate Polymers
Volume	90
Issue number	3
Pages (from-to)	1273-1280
Number of pages	8
ISSN	0144-8617
DOIs	https://doi.org/10.1016/j.carbpol.2012.06.070
Publication status	Published - 15 Oct 2012

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title = "Regioselective fluorescent labeling of N,N,N-trimethyl chitosan via oxime formation",

abstract = "Fluorescent labeling of chitosan and its derivatives is widely used for in vitro visualization and is accomplished by random introduction of the fluorophore to the polymer backbone, conceivably altering the bioactivity of the polymer. Here, we report for the first time the regioselective conjugation of a fluorophore to the reducing end of a fully N,N,N-trimethylated chitosan (TMC) by oxime formation. End-labeled conjugation of 5-(2-((aminooxyacetyl)amino) ethylamino)naphthalene-1-sulfonic acid (EDANS-O-NH2) fluorophore to TMC to form TMC-oxime-EDANS (f-TMC) was confirmed by 1H NMR and fluorescence spectroscopy. Average molecular weight calculations of f-TMC with 1H NMR and fluorescence spectroscopy gave similar results or ∼7.7 kDa. f-TMC in human bronchial epithelial cells was both cell membrane bound as well as intracellularly localized. This demonstrates the proof-of-concept for selective oxime formation at the reducing end of a chitosan derivative, which can be used for tracking chitosan in gene and drug delivery purposes and gives rise to further modifications with other functional groups.",

author = "Benediktsd{\'o}ttir, {Berglind E.} and S{\o}rensen, {Kasper Kildegaard} and Thygesen, {Mikkel Boas} and Jensen, {Knud J{\o}rgen} and Th{\'o}rarinn Gudj{\'o}nsson and {\'O}lafur Baldursson and M{\'a}r M{\'a}sson",

year = "2012",

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doi = "10.1016/j.carbpol.2012.06.070",

language = "English",

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TY - JOUR

T1 - Regioselective fluorescent labeling of N,N,N-trimethyl chitosan via oxime formation

AU - Benediktsdóttir, Berglind E.

AU - Sørensen, Kasper Kildegaard

AU - Thygesen, Mikkel Boas

AU - Jensen, Knud Jørgen

AU - Gudjónsson, Thórarinn

AU - Baldursson, Ólafur

AU - Másson, Már

PY - 2012/10/15

Y1 - 2012/10/15

N2 - Fluorescent labeling of chitosan and its derivatives is widely used for in vitro visualization and is accomplished by random introduction of the fluorophore to the polymer backbone, conceivably altering the bioactivity of the polymer. Here, we report for the first time the regioselective conjugation of a fluorophore to the reducing end of a fully N,N,N-trimethylated chitosan (TMC) by oxime formation. End-labeled conjugation of 5-(2-((aminooxyacetyl)amino) ethylamino)naphthalene-1-sulfonic acid (EDANS-O-NH2) fluorophore to TMC to form TMC-oxime-EDANS (f-TMC) was confirmed by 1H NMR and fluorescence spectroscopy. Average molecular weight calculations of f-TMC with 1H NMR and fluorescence spectroscopy gave similar results or ∼7.7 kDa. f-TMC in human bronchial epithelial cells was both cell membrane bound as well as intracellularly localized. This demonstrates the proof-of-concept for selective oxime formation at the reducing end of a chitosan derivative, which can be used for tracking chitosan in gene and drug delivery purposes and gives rise to further modifications with other functional groups.

AB - Fluorescent labeling of chitosan and its derivatives is widely used for in vitro visualization and is accomplished by random introduction of the fluorophore to the polymer backbone, conceivably altering the bioactivity of the polymer. Here, we report for the first time the regioselective conjugation of a fluorophore to the reducing end of a fully N,N,N-trimethylated chitosan (TMC) by oxime formation. End-labeled conjugation of 5-(2-((aminooxyacetyl)amino) ethylamino)naphthalene-1-sulfonic acid (EDANS-O-NH2) fluorophore to TMC to form TMC-oxime-EDANS (f-TMC) was confirmed by 1H NMR and fluorescence spectroscopy. Average molecular weight calculations of f-TMC with 1H NMR and fluorescence spectroscopy gave similar results or ∼7.7 kDa. f-TMC in human bronchial epithelial cells was both cell membrane bound as well as intracellularly localized. This demonstrates the proof-of-concept for selective oxime formation at the reducing end of a chitosan derivative, which can be used for tracking chitosan in gene and drug delivery purposes and gives rise to further modifications with other functional groups.

U2 - 10.1016/j.carbpol.2012.06.070

DO - 10.1016/j.carbpol.2012.06.070

M3 - Journal article

C2 - 22939341

SN - 0144-8617

VL - 90

SP - 1273

EP - 1280

JO - Carbohydrate Polymers

JF - Carbohydrate Polymers

IS - 3

ER -

Regioselective fluorescent labeling of N,N,N-trimethyl chitosan via oxime formation

Abstract

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