title: Mechanical and diffusive properties of homogeneous alginate gels in form of particles and cylinders.
abstract: In this study, alginate polymers are used to get homogeneous cylindrical or spherical gels. MRI techniques are employed to study homogeneity of these gels. Four different alginates are used and, for each one, five different concentrations for mechanical tests and three different concentrations for release tests are studied. Mechanical tests are performed to get gels' linear viscoelasticity region and then to evaluate their crosslink density in relation to polymer concentration. Afterwards, three model molecules (theophylline, vitamin B(12), and myoglobin) are loaded within gels to study the release kinetics in water from both cylindrical and spherical gels. Diffusion coefficients calculated from these experiments are then used to estimate the polymeric network mesh wideness. This work shows how crosslink density increases with polymer concentration regardless of the alginate type considered. In addition, while vitamin B(12) diffusion coefficient is inversely proportional to crosslink density, myoglobin is too large to diffuse through the polymeric network, whatever the alginate type and polymer concentration. At the same time, theophylline is too small to be sensibly affected by increasing the polymeric network crosslink density. Finally, MRI analysis and vitamin B(12) diffusion coefficient values prove that, structurally speaking, cylinders and spheres are similar and homogeneous.
authors.affiliation: PROTOS Research Institute, Viale XX Settembre 11, Trieste, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Pasut
authors.forename: R
authors.initials: R
authors.lastname: Toffanin
authors.forename: D
authors.initials: D
authors.lastname: Voinovich
authors.forename: C
authors.initials: C
authors.lastname: Pedersini
authors.forename: E
authors.initials: E
authors.lastname: Murano
authors.forename: M
authors.initials: M
authors.lastname: Grassi
mesh_terms: D000464:Alginates / Q000737:chemistry*; D003432:Cross-Linking Reagents; D004548:Elasticity; D005782:Gels / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D007700:Kinetics; D008279:Magnetic Resonance Imaging; D008863:Microspheres; D009211:Myoglobin / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013806:Theophylline / Q000737:chemistry; D014783:Viscosity; D014805:Vitamin B 12 / Q000737:chemistry; D014867:Water
chemical_list: D000464:Alginates; D003432:Cross-Linking Reagents; D005782:Gels; D006603:Hexuronic Acids; D009211:Myoglobin; D011108:Polymers; D014867:Water; D020723:Glucuronic Acid; D013806:Theophylline; D014805:Vitamin B 12