Three-Dimensional Patterning of Poly(Ethylene Glycol) Hydrogels Through Surface-Initiated Photopolymerization

Photopolymerizable hydrogels have been investigated extensively for biomedical applications, specifically in the area of tissue engineering. While fabrication approaches have shown promise in designing hydrogel scaffolds that guide cell function, the ability to spatially control localization in three-dimensions has been limited. We have developed a method for generating two-dimensional and three-dimensional (3D) patterns within multilayered poly(ethylene glycol) diacrylate (PEG-DA) hydrogels. Covalently attached hydrogel layers are formed using precursor solutions with a 10:1 mole ratio of PEG-DA to PEG-aminoacrylate (Acr-PEG-NH2). Upon illumination of the precursor with visible light (λ = 514 nm), a hydrogel layer forms with pendant amine groups induced by the presence of Acr-PEG-NH2 macromer. Pendant amine groups are further functionalized with free carboxyl groups present on the visible light photoinitiator eosin, allowing for the formation of subsequent hydrogel layers. Using noncontact photolithograp...