title: Impact of degradable macromer content in a poly(ethylene glycol) hydrogel on neural cell metabolic activity, redox state, proliferation, and differentiation.
abstract: Hydrogels that degrade at different rates were prepared by copolymerizing slowly degrading macromer poly(ethylene glycol) (PEG) dimethacrylate with a faster degrading macromer poly(lactic acid)-b-PEG-b-poly(lactic acid) dimethacrylate. A clinically relevant population of neural cells composed of differentiated neurons and multipotent precursor cells was cultured within hydrogels. Within 2 h after encapsulation, metabolic activity was higher in hydrogels prepared with increasing levels of degradable content. This improvement was accompanied by a reduction in intracellular redox state and an increase in the fraction of glutathione in the reduced state, both of which persisted throughout 7 days of culture and which may be the result of radical scavenging by lactic acid. Importantly, an increase in cellular proliferation was observed in gels prepared with increasing degradable macromer content after 7 days of growth without a shift in the cellular composition of the culture toward the glial cell phenotype. The findings of this study provide additional insight into the growth of neural cells in PEG-based hydrogels. Results suggest that lactic acid released during gel degradation may impact the function of encapsulated cells, a finding of general interest to biomaterials scientists who focus on the development of degradable polymers for cell culture and drug delivery devices.
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309-0424, USA.
authors.forename: Kyle J
authors.initials: KJ
authors.lastname: Lampe
authors.forename: Kimberly B
authors.initials: KB
authors.lastname: Bjugstad
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Mahoney
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry* / Q000494:pharmacology*; D019344:Lactic Acid / Q000737:chemistry*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D011091:Polyesters; D011092:Polyethylene Glycols / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D011108:Polymers / Q000737:chemistry* / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering
chemical_list: D011091:Polyesters; D011108:Polymers; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D019344:Lactic Acid; D011092:Polyethylene Glycols; C033616:poly(lactide); D000255:Adenosine Triphosphate; D004247:DNA; D005978:Glutathione