Preparation and characterization of poly(ethylene glycol)-crosslinked reacetylated chitosans

Pozzo, Alma Dal; Vanini, Laura; Fagnoni, Maurizio; Guerrini, Marco; Benedittis, A. De; Müzzarelli, Riccardo A.A.

doi:10.1016/s0144-8617(99)00134-4

Cited by 102 publications

(49 citation statements)

References 18 publications

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“…Chemical hydrogels are formed by irreversible covalent links. Crosslinking procedure may be performed by reaction of chitosan with different bifunctional reagents such as glutaraldehyde [1,5], carbondiimide [6], crown ether [7], dicarboxylic acids [8], poly(ethylene glycol) dialdehydes [9] and glyoxal [10]. Crosslinking promotes the formation of uniform porous network-like structure of chitosan, change its crystal structure from a-type to b-type and may also smoothen the surface of chitosan [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of chitosan membranes by using a combined freeze gelation and mild crosslinking method

Orrego

Valencia

2008

Bioprocess Biosyst Eng

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When gelification is performed by freezing-thawing repeated cycles, the resultant gel-like polymer systems are called cryogels. This work aims to assess the effect of the addition of glutaraldehyde and 18 Crown Ether-6 on surface properties and protein loading of dried chitosan cryogel films. Residual water content of treated chitosan membranes ranged between 11.93 and 13.86%, while their water activities vary from 0.5 to 0.7 (measured from 4 to 60 degrees C). Based on thermal data, water evaporation peak and degradation temperatures of chitosan membranes shifted to a higher temperature for crosslinked samples. X-ray diffractograms provide high values of crystallinity for all the samples (70.67-92.86%), the highest value being for the glutaraldehyde-treated membrane. Candida rugosa lipase can be immobilized successfully on chitosan membranes. Lipase immobilized on glutaraldehyde-crosslinked chitosan yielded the highest efficiency in terms of total coupled protein and protein loading efficiency.

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Section: Introductionmentioning

confidence: 99%

Preparation and characterization of chitosan membranes by using a combined freeze gelation and mild crosslinking method

Orrego

Valencia

2008

Bioprocess Biosyst Eng

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“…Generally, commercial chitosan with large molecular weight can be soluble only in weak acid water solution such as aqueous acetic acid. In some reports on fiber processings, chitosan can also be used as antibacterial reagents or dyeing improvement reagents, where chitosan was fixed on fibers using crosslinking reactions of chitosan, or mixed into fibers without chemical bonds between chitosan and fibers [3][4][5][6]. Therefore, the introduced chitosan were gradually off from the fiber surface by laundry using water.…”

Section: Introductionmentioning

confidence: 99%

Reaction of Nylon 6 Fiber with Chitosan using Cyanuric Chloride

2007

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“…SEM images also describing the compatibility of OCMC with chitosan by its properly distributed pores throughout the film which also showing its three dimensional porous structure which is very useful for its further application in biomedical field as the covalent crosslinking leads to the formation of a permanent network allowing the free diffusion of water and enhancing the mechanical properties of the gel. As a result of these interesting characteristics, covalently crosslinked compound have two main applications, namely as drug delivery systems allowing release of bioactive materials by diffusion and as permanent networks used, for example, as scaffolds in cell culture and whatever the type of structure, networks containing covalently crosslinked chitosan are considered as porous [41][42][43][44]. This term is used to describe networks containing free water that can diffuse through the hydrogel.…”

Section: Resultsmentioning

confidence: 99%

Structural characterization of chitosan and oxidized carboxymethyl cellulose based freeze-dried films

2010

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The conversion of dihydroxyl groups to dialdehyde by periodate oxidation is a useful method widely used in derivatization of cellulose. Periodate oxidation is a highly specific reaction to convert 1,2-dihydroxyl groups to paired aldehyde groups without significant side reactions. This reaction cleaves the C2-C3 bond; the resulting compound is the dialdehyde cellulose (DAC). These aldehyde groups of carboxymethyl cellulose interact with amino group of chitosan and their interaction results in the formation Schiff's base with enhanced properties of both the polymers, i.e., of chitosan and carboxymethyl cellulose. Interaction of chitosan and oxidized carboxymethyl cellulose (OCMC) has been carried out with three combinations, i.e., 5, 10, and 15 wt% OCMC with rest of chitosan in 2% lactic acid solution. This new compound is covalently crosslinked which has been analyzed by various techniques like FTIR, TGA, XRD, and SEM.

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Preparation and characterization of poly(ethylene glycol)-crosslinked reacetylated chitosans

Cited by 102 publications

References 18 publications

Preparation and characterization of chitosan membranes by using a combined freeze gelation and mild crosslinking method

Preparation and characterization of chitosan membranes by using a combined freeze gelation and mild crosslinking method

Reaction of Nylon 6 Fiber with Chitosan using Cyanuric Chloride

Structural characterization of chitosan and oxidized carboxymethyl cellulose based freeze-dried films

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