title: N-(furfural) chitosan hydrogels based on Diels-Alder cycloadditions and application as microspheres for controlled drug release.
abstract: In this study, chitosan was chemically modified by reductive amination in a two-step process. The synthesis of N-(furfural) chitosan (FC) was confirmed by FT-IR and (1)H NMR analysis, and the degrees of substitution were estimated as 8.3 and 23.8%. The cross-linkable system of bismaleimide (BM) and FC shows that FC shared properties of furan-maleimide chemistry. This system produced non-reversible hydrogel networks by Diels-Alder cycloadditions at 85 °C. The system composed of BM and FC (23.8% substitution) generated stronger hydrogel networks than those of FC with an 8.3% degree of substitution. Moreover, the FC-BM system was able to produce hydrogel microspheres. Environmental scanning electron microscopy revealed the surface of the microspheres to be non-porous with small protuberances. In water, the microspheres swelled, increasing their volume by 30%. Finally, microspheres loaded with methylene blue were able to release the dye gradually, obeying second-order kinetics for times less than 600 min. This behavior suggests that diffusion is governed by the relaxation of polymer chains in the swelled state, thus facilitating drug release outside the microspheres.
authors.affiliation: Laboratorio de Polímeros Naturales, Centro de Investigación en Alimentación y Desarrollo A.C., Carretera al Varadero Nacional km 6.6, Colonia Las Playitas, Guaymas CP 85480, Sonora, Mexico.
authors.forename: Marcelino
authors.initials: M
authors.lastname: Montiel-Herrera
authors.affiliation: Materials Engineering Department, Engineering School of São Carlos, University of São Paulo, 13566-590 São Carlos, Brazil.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Gandini
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universtät Münster, Hindernburgplatz 55, 48143 Münster, Germany; Laboratorio de Biopolímeros (CTAOA), Centro de Investigación en Alimentación y Desarrollo A.C., Carretera a La Victoria km 0.6, Ejido La Victoria, CP 83000 Hermosillo, Sonora, Mexico.
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Goycoolea
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, 1306 E. University Blvd, Tucson, AZ 85721, USA.
authors.forename: Neil E
authors.initials: NE
authors.lastname: Jacobsen
authors.affiliation: Laboratorio de Biopolímeros (CTAOA), Centro de Investigación en Alimentación y Desarrollo A.C., Carretera a La Victoria km 0.6, Ejido La Victoria, CP 83000 Hermosillo, Sonora, Mexico.
authors.forename: Jaime
authors.initials: J
authors.lastname: Lizardi-Mendoza
authors.affiliation: Laboratorio de Polímeros Naturales, Centro de Investigación en Alimentación y Desarrollo A.C., Carretera al Varadero Nacional km 6.6, Colonia Las Playitas, Guaymas CP 85480, Sonora, Mexico.
authors.forename: Maricarmen
authors.initials: M
authors.lastname: Recillas-Mota
authors.affiliation: Laboratorio de Polímeros Naturales, Centro de Investigación en Alimentación y Desarrollo A.C., Carretera al Varadero Nacional km 6.6, Colonia Las Playitas, Guaymas CP 85480, Sonora, Mexico. Electronic address: waldo@ciad.mx.
authors.forename: Waldo M
authors.initials: WM
authors.lastname: Argüelles-Monal
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D057930:Click Chemistry; D061565:Cycloaddition Reaction; D003692:Delayed-Action Preparations / Q000737:chemistry; D005662:Furaldehyde / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008301:Maleimides / Q000737:chemistry*; D008863:Microspheres; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D003692:Delayed-Action Preparations; D020100:Hydrogels; D008301:Maleimides; D048271:Chitosan; D005662:Furaldehyde
keywords: Chitosan; Click chemistry; Diels–Alder; Furans; Hydrogels; Reductive amination