title: Methods for photocrosslinking alginate hydrogel scaffolds with high cell viability.
abstract: Methods for seeding high-viability (>85%) three-dimensional (3D) alginate-chondrocyte hydrogel scaffolds are presented that employ photocrosslinking of methacrylate-modified alginate with the photoinitiator VA-086. Comparison with results from several other photoinitiators, including Irgacure 2959, highlights the role of solvent, ultraviolet exposure, and photoinitiator cytotoxicity on process viability of bovine chondrocytes in two-dimensional culture. The radicals generated from VA-086 photodissociation are shown to be noncytotoxic at w/v concentrations up to 1.5%, enabling photocrosslinking without significant cell death. The applicability of these photoinitiators for generating 3D tissue-engineered constructs is evaluated by measuring cell viability in 3D constructs with aggregate moduli in the 10-20 kPa range. Hydrogels with encapsulated bovine chondrocytes were constructed with >85% viability using VA-086. While the commonly used Irgacure 2959 is noncytotoxic in its native state and crosslinks the alginate at weight fractions much lower than VA-086, the cytotoxicity of IRG2959's photogenerated radical leads to viabilities below 70% in the conditions tested.
authors: Department of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, USA.
authors: Andrew D
authors: AD
authors: Rouillard
authors: Caroline M
authors: CM
authors: Berglund
authors: Jae Youn
authors: JY
authors: Lee
authors: William J
authors: WJ
authors: Polacheck
authors: Yvonne
authors: Y
authors: Tsui
authors: Lawrence J
authors: LJ
authors: Bonassar
authors: Brian J
authors: BJ
authors: Kirby
mesh_terms: D000081:Acetamides / Q000494:pharmacology*; D000464:Alginates / Q000494:pharmacology*; D000818:Animals; D001391:Azo Compounds / Q000494:pharmacology*; D002358:Cartilage, Articular / Q000166:cytology; D002417:Cattle; D002449:Cell Aggregation / Q000187:drug effects / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D020723:Glucuronic Acid / Q000494:pharmacology; D006603:Hexuronic Acids / Q000494:pharmacology; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology*; D008027:Light; D018613:Microscopy, Confocal; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: C000605936:2,2-azobis(2-methyl-N-(2-hydroxyethyl)propionamide; D000081:Acetamides; D000464:Alginates; D001391:Azo Compounds; D003432:Cross-Linking Reagents; D006603:Hexuronic Acids; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D020723:Glucuronic Acid