ABSTRACT
This chapter presents an overview of recent exciting developments in click hydrogels and their applications for regenerative engineering. The resultant hydrogels formed within 5–60 minutes at physiological temperature due to 1, 3-dipolar cycloaddition of azides with electron-deficient alkynes and gave rise to mechanically robust materials. The photochemical processes are most widely utilized and are particularly attractive for designing thiol-ene hydrogels for biomedical applications as they afford spatiotemporal control of the polymerization by regulating the application of light. The properties of thiol-(meth)acrylate photo click hydrogels can be tuned by changing light intensities, light exposure time, PEG functionality (4-arm vs. 2-arm), and the polymer weight percentage. The Feijen group cross-linked thiolated HA (HA-SH) and PEG vinyl sulfone (PEG-VS) macromers via Michael-type additions to form hydrogels under physiological conditions. Various hydrogels have been fabricated from PEG or the polysaccharide adipic acid dihydrazide (ADH) and aldehyde derivatives via aldehyde-hy.
