title: The effect of oxidation on the degradation of photocrosslinkable alginate hydrogels.
abstract: Recently, we reported on a new photocrosslinkable alginate-based hydrogel, which has controllable physical and cell adhesive properties. The macromer solution containing cells can be injected in a minimally invasive manner into a defect site and crosslinked while maintaining high cell viability. The number of hydrolyzable ester bonds in the formed crosslinks may be controlled by altering the degree of methacrylation on the alginate polymer backbone. However, the degradation rate of the hydrogels has been found to be slower in vivo than in vitro. The purpose of this study was to develop photocrosslinked alginate hydrogels with an increased range of biodegradation rates for more rapid in vivo biodegradation in regenerative medicine and bioactive factor delivery applications. Therefore, we oxidized alginate prior to methacrylation to change the uronate residue conformations to an open-chain adduct, which makes it more vulnerable to hydrolysis. Here, we demonstrate that the swelling behavior, degradation profiles, and storage moduli of photocrosslinked hydrogels formed from oxidized, methacrylated alginates (OMAs) are tunable by varying the degree of alginate oxidation. The OMA macromers and photocrosslinked OMA hydrogels exhibited cytocompatibility when cultured with human bone marrow-derived mesenchymal stem cells (hBMMSCs). In addition, hMSCs derived from bone marrow or adipose tissue photoencapsulated within these hydrogels remained viable, and their proliferation rate was a function of alginate oxidation level and initial hydrogel weight fraction. Oxidation permits a wider range of photocrosslinked OMA hydrogels physical properties, which may enhance these therapeutic materials' utility in tissue engineering and other biomedical applications.
authors.affiliation: Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Oju
authors.initials: O
authors.lastname: Jeon
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Alt
authors.forename: Shaoly M
authors.initials: SM
authors.lastname: Ahmed
authors.forename: Eben
authors.initials: E
authors.lastname: Alsberg
mesh_terms: D000464:Alginates / Q000138:chemical synthesis / Q000737:chemistry*; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects; D002448:Cell Adhesion / Q000187:drug effects / Q000528:radiation effects; D048430:Cell Shape / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D055119:Elastic Modulus / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D007700:Kinetics; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects; D008689:Methacrylates / Q000737:chemistry; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D012212:Rheology / Q000187:drug effects / Q000528:radiation effects; D013499:Surface Properties / Q000187:drug effects / Q000528:radiation effects
chemical_list: D000464:Alginates; D003432:Cross-Linking Reagents; D020100:Hydrogels; D008689:Methacrylates