title: Nitrocinnamate-functionalized gelatin: synthesis and "smart"hydrogel formation via photo-cross-linking.
abstract: Gelatin having p-nitrocinnamate pendant groups (Gel-NC) was prepared via an efficient one-pot synthesis, yield >87%. (1)H NMR data indicated that 1 mol of gelatin was modified with 18 +/- 6 mol of the photosensitive group. Upon exposure to low-intensity 365 nm UV light and in the absence of photoinitiators or catalysts, Gel-NC cross-linked within minutes into a gelatin-based hydrogel as monitored by UV-vis spectroscopy. The degree of swelling of this biodegradable hydrogel in aqueous solutions responded to changes in Gel-NC concentration levels, the ionic strength of the aqueous solutions, and photo-cross-linking time. Topography changes associated with phase transition resulting from "photocleavage" of the hydrogel network with 254 nm UV light were studied with AFM. Both Gel-NC and its hydrogel expressed low toxicity to human neonatal fibroblast cells. In addition, gelatin-based microgels were prepared via the photo-cross-linking of Gel-NC within inverse micelles.
authors.affiliation: Department of Chemistry, University of Miami, Coral Gables, Florida 33146, USA.
authors.forename: Kerim M
authors.initials: KM
authors.lastname: Gattás-Asfura
authors.forename: Eric
authors.initials: E
authors.lastname: Weisman
authors.forename: Fotios M
authors.initials: FM
authors.lastname: Andreopoulos
authors.forename: Miodrag
authors.initials: M
authors.lastname: Micic
authors.forename: Bill
authors.initials: B
authors.lastname: Muller
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Sirpal
authors.forename: Si M
authors.initials: SM
authors.lastname: Pham
authors.forename: Roger M
authors.initials: RM
authors.lastname: Leblanc
mesh_terms: D002934:Cinnamates / Q000138:chemical synthesis* / Q000528:radiation effects; D003432:Cross-Linking Reagents / Q000138:chemical synthesis* / Q000528:radiation effects; D005780:Gelatin / Q000138:chemical synthesis* / Q000528:radiation effects; D020100:Hydrogels / Q000138:chemical synthesis* / Q000528:radiation effects; D010775:Photic Stimulation / Q000379:methods; D014466:Ultraviolet Rays
chemical_list: D002934:Cinnamates; D003432:Cross-Linking Reagents; D020100:Hydrogels; D005780:Gelatin