title: Preparation of pH- and ionic-strength responsive biodegradable fumaric acid crosslinked carboxymethyl cellulose.
abstract: A novel biodegradable sodium carboxymethyl cellulose (NaCMC)-based hydrogel was synthesized by using fumaric acid (FA) as a crosslinking agent at various ratios. Hydrogels (CMCF) were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Swelling behaviors of hydrogels were investigated in distilled water, various salt, and pH solutions. The FTIR results indicated the crosslinking between carboxyl groups of FA with hydroxyl group of NaCMC through ester formation. AFM analyses showed that roughness of hydrogel surface decreased with increasing crosslinker concentration. The swelling capacity decreased with an increase in charge of the metal cation (Al(3+)<Ca(2+)<Na(+)). In order to investigate reversible pH sensitivity of CMCF hydrogels, pH-dependent swelling was studied at pH 2 and 10. Reversible pH-responsiveness of CMCF hydrogels was achieved. CMCF hydrogels containing the greatest ratio of FA exhibited the longest biodegradation time with a half life of 21 h using cellulase.
authors.affiliation: Dokuz Eylül University, Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Izmir, Turkey.
authors.forename: Emine
authors.initials: E
authors.lastname: Akar
authors.forename: Aylin
authors.initials: A
authors.lastname: Altınışık
authors.forename: Yoldaş
authors.initials: Y
authors.lastname: Seki
mesh_terms: D002152:Calorimetry, Differential Scanning; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry* / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000378:metabolism*; D005650:Fumarates / Q000378:metabolism*; D020100:Hydrogels / Q000138:chemical synthesis*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009994:Osmolar Concentration; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D003432:Cross-Linking Reagents; D005650:Fumarates; D020100:Hydrogels; C032005:fumaric acid; D002266:Carboxymethylcellulose Sodium