title: Modification and cross-linking parameters in hyaluronic acid hydrogels--definitions and analytical methods.
abstract: Definitions and methods for the quantification of degree of modification and cross-linking in cross-linked hyaluronic acid (HA) hydrogels are outlined. A novel method is presented in which the HA hydrogel is degraded by the enzyme chondroitinase AC and the digest product analyzed by size exclusion chromatography combined with electrospray ionization mass spectrometry (SEC-ESI-MS). This method allows for the determination of effective cross-linker ratio (CrR) which together with the degree of modification (MoD), determined by, e.g. (1)H NMR spectroscopy, enables the calculation of the degree of substitution (DS) and degree of cross-linking (CrD). The method, could be applicable to the major cross-linked HA hydrogels currently on the market, and is exemplified here by application to two HA hydrogels. The definitions and methods presented are important contributions in attempts to find relationships between MoD, DS and CrD to mechanical properties as well as to biocompatibility of HA hydrogels.
authors.affiliation: Department of Chemistry, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden.
authors.forename: Lennart
authors.initials: L
authors.lastname: Kenne
authors.forename: Suresh
authors.initials: S
authors.lastname: Gohil
authors.forename: Eva M
authors.initials: EM
authors.lastname: Nilsson
authors.forename: Anders
authors.initials: A
authors.lastname: Karlsson
authors.forename: David
authors.initials: D
authors.lastname: Ericsson
authors.forename: Anne
authors.initials: A
authors.lastname: Helander Kenne
authors.forename: Lars I
authors.initials: LI
authors.lastname: Nord
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D006018:Glycols / Q000737:chemistry; D006820:Hyaluronic Acid / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*
chemical_list: D006018:Glycols; D020100:Hydrogels; D006820:Hyaluronic Acid