One-pot synthesis of a chitosan-based hydrogel as a potential device for magnetic biomaterial

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This describes the cross-linking/co-polymerization reaction of chitosan ( CS), acrylic acid (AAc), and N, N'-methylenebisacrylamide (MBA) in the presence of citrate-covered-gamma-Fe(2)O(3) nanoparticules. A gelling process was verified by means of spectroscopic methods; Fourier transform infrared (FT-IR) and solid-state (13)C-CP/MAS nuclear magnetic resonance (NMR). The corresponding signals of the gelling process, in the (13)C NMR spectra, for the magnetic hydrogel were shifted to lower values due to embedding of the citrate-covered-gamma-Fe(2)O(3) nanoparticules. The X-ray diffraction (XRD) confirmed that the crystallinity of the magnetic hydrogel exhibited a different crystalline structure to that without magnetic properties. The Mossbauer and magnetization analysis revealed that the magnetic hydrogel displays a high lattice strain, due to bonded iron atom covalence and superparamagnetism. From scanning electronic microscope (SEM) micrographs, no separation phase coexists between the magnetic nanoparticules and cross-linked hydrogel, indicating an excellent dispersion throughout the hydrogel. The swelling rate was dependent on the cross-linking degree of the hydrogel and ionic strength of the aqueous solution. (c) 2009 Elsevier B.V. All rights reserved.3211726362642Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2008/00285-7

Copolymer Hydrogel Microspheres Consisting of Modified Sulfate Chondroitin-co-Poly(N-isopropylacrylamide)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Modified chondroitin sulfate (pi-CdS) microspheres were synthesized by way of crosslinking-copolymerization reaction with N-isopropylacrylamide (NIPAAm), yielding CdS-co-PNIPAAm copolymer network. The incorporation of vinyl groups onto the CdS was processed with the use of glycidyl methacrylate (GMA) in an aqueous solution of pH 3.5 under stirring speed of 800 rpm at 50 degrees C. C-13 NMR and H-1 NMR spectra of CdS treated with the GMA indicated the formation of 3-methacryloyl-1-glyceryl ester of pi-CdS and 3-methacryloyl-2-glyceryl ester of pi-CdS that are the reaction products resultant of an epoxide ring-opening mechanism via. The synthesis of microspheres was performed via radical reaction of the vinyl groups at the pi-CdS with vinyl groups at the NIPAAm in a water-benzyl alcohol microemulsion. The formation of spherical structures is the result of the polymerization-crosslinking reaction of the pi-CdS with the NIPAAm monomers at the droplets of water, in view that both reactants have hydrophilic characteristics at the temperature at which the reaction was processed. The pure CdS hydrogel microspheres showed a slightly cracked structure with a lower diameter range while the CdS-co-PNIPAAm hydrogel microspheres showed a flat and tight structure with a more regular mass distribution. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 2726-2733, 2011121527262733Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [151999/2008-2]FAPESP [06/50952-4