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Molecularly Imprinted Chitosan-Genipin Hydrogels with Recognition Capacity toward o-Xylene

A molecularly imprinted material was developed from hydrogels of chitosan (CS) cross-linked with genipin (GNP) using o-xylene as the template molecule. Gelling time, mechanical, and diffusion properties of CS-GNP hydrogels were initially investigated to establish optimal conditions to prepare molecu...

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Bibliographic Details
Published in:Biomacromolecules 2007-01, Vol.8 (11), p.3355-3364
Main Authors: Espinosa-Garcia, Bibiana M, Arguelles-Monal, Waldo M, Hernandez, Javier, Felix-Valenzuela, Leticia, Acosta, Niuris, Goycoolea, Francisco M
Format: Article
Language:English
Online Access:Get full text
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Summary:A molecularly imprinted material was developed from hydrogels of chitosan (CS) cross-linked with genipin (GNP) using o-xylene as the template molecule. Gelling time, mechanical, and diffusion properties of CS-GNP hydrogels were initially investigated to establish optimal conditions to prepare molecularly imprinted hydrogels (MIHs). The elastic modulus was found to be directly proportional to the degree of cross-linking (R = moles of genipin/moles of glucosamine) while the diffusion of water, as monitored by magnetic resonance imaging, decreased with R. CS-GNP hydrogels of varying R were imprinted with o-xylene (MIHdo-xylene). The adsorption capacity of o-xylene by MIH sub(o)-xylene was greater than the corresponding control hydrogels, particularly at R = 0.25. Freundlich isotherms yielded a better fitness than Langmuir ones and afforded n and Q sub(max) values of 2.55 and 103.3 mg/g, respectively. The imprinted hydrogel showed the highest adsorption capacity for o- xylene; however, the material was not highly selective as it also exhibited the capacity to adsorb m- and p-xylene isomers. In turn, the MIH sub(o)-xylene showed a low adsorption when 2-fluorotoluene was used in rebinding experiments, suggesting that molecular recognition by the binding sites is influenced by the electronic and steric properties of the analyte molecule, thus effectively confirming the imprinting effect within the MIH sub(o)-xylene network. This work opens the possibility to future development of materials with the capacity to adsorb o-xylene analogue molecules such as contaminants bearing chlorinated aromatic structures.
ISSN:1525-7797
1526-4602
DOI:10.1021/bm700458aPII:S1525-7797(70)00458-0