title: Low- and high-resolution nuclear magnetic resonance (NMR) characterisation of hyaluronan-based native and sulfated hydrogels.
abstract: Hyaluronan-based hydrogels were synthesised using different crosslinking agents, such as 1,3-diaminopropane (1,3-DAP) and 1,6-diaminohexane (1,6-DAE). The hydrogels were sulfated to provide materials (Hyal-1,3-DAP, Hyal-1,6-DAE, HyalS-1,3-DAP and HyalS-1,6-DAE) that were characterised by both high- and low-resolution nuclear magnetic resonance (NMR) spectroscopy. The (13)C NMR spectra of the materials were analysed to identify, characterise and study the crosslinking degree of the hydrogels. The crosslinking degree was also determined by potentiometric titration and the effectiveness of the two techniques was compared. Measurements of longitudinal relaxation times (spin-lattice) and of NOE enhancement were used to study the mobility of the hydrogels. Low-resolution NMR studies allowed the determination of the water transport properties in the hydrogels. In addition, the swelling degree for the various hydrogels was calculated as a function of the longitudinal and transversal relaxation times of the water molecules. Lastly, the self-diffusion coefficients of the water in interaction with the four polysaccharides were measured by the pulsed field gradient spin echo (PFGSE) sequence.
authors.affiliation: CRISMA and Department of Chemical and Biosystem Sciences and Technologies, University of Siena, Italy. barbucci@unisi.it
authors.forename: Rolando
authors.initials: R
authors.lastname: Barbucci
authors.forename: Gemma
authors.initials: G
authors.lastname: Leone
authors.forename: Antonio
authors.initials: A
authors.lastname: Chiumiento
authors.forename: Maria Enrica
authors.initials: ME
authors.lastname: Di Cocco
authors.forename: Giovanni
authors.initials: G
authors.lastname: D'Orazio
authors.forename: Raffaella
authors.initials: R
authors.lastname: Gianferri
authors.forename: Maurizio
authors.initials: M
authors.lastname: Delfini
mesh_terms: D002240:Carbohydrate Sequence; D003432:Cross-Linking Reagents / Q000737:chemistry; D006820:Hyaluronic Acid / Q000737:chemistry*; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016062:Porosity; D012815:Signal Processing, Computer-Assisted; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013463:Sulfuric Acid Esters / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D003432:Cross-Linking Reagents; D020100:Hydrogels; D013463:Sulfuric Acid Esters; D006820:Hyaluronic Acid