title: Effects of physical and chemical treatments on the molecular weight and degradation of alginate-hydroxyapatite composites.
abstract: Degradation of alginate remains a critical issue to allow predictable biological performance upon implantation of alginate-based materials. Therefore, the objective of the current study is to compare the effects of γ-irradiation (dry state, 20-80 kGy), partial (1 and 4%) periodate oxidation (aqueous solution), and autoclaving (dry state) on the molecular weight of alginate, as well as the degradation behavior of alginate-based composites. The results show that γ-irradiation is by far the most destructive technique characterized by strongly reduced molecular weights and rapid loss of composite integrity upon soaking in simulated body fluid. Partial periodate oxidation is less destructive as characterized by more moderate decreases in molecular weight, but the production of hydrolytically labile bonds compromises the integrity of the resulting composites. Autoclaving is shown to be a powerful tool to reduce the molecular weight of alginate in a controllable and mild manner without compromising the integrity of the resulting alginate-hydroxyapatite composites, simply by increasing the number of repetitive autoclaving cycles.
authors.affiliation: Department of Biomaterials, Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands; EMCM B.V., Middenkampweg 17, 6545, CH Nijmegen, The Netherlands.
authors.forename: Daniel Alves
authors.initials: DA
authors.lastname: Cardoso
authors.forename: Ann-Sissel
authors.initials: AS
authors.lastname: Ulset
authors.forename: Johan
authors.initials: J
authors.lastname: Bender
authors.forename: John A
authors.initials: JA
authors.lastname: Jansen
authors.forename: Bjørn E
authors.initials: BE
authors.lastname: Christensen
authors.forename: Sander C G
authors.initials: SC
authors.lastname: Leeuwenburgh
mesh_terms: D000464:Alginates / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D005720:Gamma Rays; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006358:Hot Temperature; D008422:Materials Testing; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010504:Periodic Acid / Q000737:chemistry
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D010504:Periodic Acid; D020723:Glucuronic Acid; D017886:Durapatite; C009288:metaperiodate
keywords: biomaterials; composites; degradation; hydrogels; radiation