Journal article
Photoinitiated alkyne-azide click and radical cross-linking reactions for the patterning of PEG hydrogels
RT Chen, S Marchesan, RA Evans, KE Styan, GK Such, A Postma, KM McLean, BW Muir, F Caruso
Biomacromolecules | Published : 2012
DOI: 10.1021/bm201802w
Abstract
The photolithographical patterning of hydrogels based solely on the surface immobilization and cross-linking of alkyne-functionalized poly(ethylene glycol) (PEG-tetraalkyne) is described. Photogenerated radicals as well as UV absorption by a copper chelating ligand result in the photochemical redox reduction of Cu(II) to Cu(I). This catalyzes the alkyne-azide click reaction to graft the hydrogels onto an azide-functionalized plasma polymer (N 3PP) film. The photogenerated radicals were also able to abstract hydrogen atoms from PEG-tetraalkyne to form poly(α-alkoxy) radicals. These radicals can initiate cross-linking by addition to the alkynes and intermolecular recombination to form the PEG ..
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Funding Acknowledgements
The authors acknowledge Assoc. Prof. J. Forsythe (Monash University) along with Dr. P. Leech and F. Glenn (CSIRO) for their generous gifts of the photoinitiator and the photomask, respectively. We also acknowledge S. M. Pereira (CSIRO) for synthesizing the ligand, A. Balachandra, K. M. Tsang, and Dr. X. Hao (CSIRO) for assistance with rheology, Dr. R. Mulder (CSIRO) for assistance with NMR analysis, Y. Gozukara (CSIRO) for ICP analysis, and Dr. J. Cervenka (University of Melbourne) for Raman analysis. This research was supported by the Australian Research Council under the Federation Fellowship, Discovery Project, and Postdoctoral Fellowship schemes and by CSIRO OCE funding.