title: Imine Hydrogels with Tunable Degradability for Tissue Engineering.
abstract: A shortage of available organ donors has created a need for engineered tissues. In this context, polymer-based hydrogels that break down inside the body are often used as constructs for growth factors and cells. Herein, we report imine cross-linked gels where degradation is controllable by the introduction of mixed imine cross-links. Specifically, hydrazide-functionalized poly(ethylene glycol) (PEG) reacts with aldehyde-functionalized PEG (PEG-CHO) to form hydrazone linked hydrogels that degrade quickly in media. The time to degradation can be controlled by changing the structure of the hydrazide group or by introducing hydroxylamines to form nonreversible oxime linkages. Hydrogels containing adipohydrazide-functionalized PEG (PEG-ADH) and PEG-CHO were found to degrade more rapidly than gels formed from carbodihydrazide-functionalized PEG (PEG-CDH). Incorporating oxime linkages via aminooxy-functionalized PEG (PEG-AO) into the hydrazone cross-linked gels further stabilized the hydrogels. This imine cross-linking approach should be useful for modulating the degradation characteristics of 3D cell culture supports for controlled cell release.
authors.affiliation: ‡Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095, United States.
authors.forename: Natalie
authors.initials: N
authors.lastname: Boehnke
authors.affiliation: §Department of Bioengineering, University of California, Los Angeles, 420 Westwood Plaza, 5121 Engineering V, Los Angeles, California 90095, United States.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Cam
authors.affiliation: ‡Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095, United States.
authors.forename: Erhan
authors.initials: E
authors.lastname: Bat
authors.affiliation: ∥Department of Chemical and Biomolecular Engineering and the California NanoSystems Institute, 420 Westwood Plaza, 5531 Boelter Hall, Los Angeles, California 90095, United States.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Segura
authors.affiliation: ‡Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095, United States.|§Department of Bioengineering, University of California, Los Angeles, 420 Westwood Plaza, 5121 Engineering V, Los Angeles, California 90095, United States.
authors.forename: Heather D
authors.initials: HD
authors.lastname: Maynard
mesh_terms: D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D006834:Hydrazines / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D011092:Polyethylene Glycols / Q000737:chemistry; D023822:Tissue Engineering
chemical_list: D006834:Hydrazines; D020100:Hydrogels; D007097:Imines; C029424:hydrazine; D011092:Polyethylene Glycols