Current methods for forming PEG hydrogels use UV light which can be cytotoxic and damaging to cells. Photoinitiated PEG hydrogels are formed by the covalent conjugation of an 8-arm PEG with a dithiol crosslinker and lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) photoinitiator in the presence of 365 nm UV light. As an alternative, these step-growth polymerized hydrogels can be formed in the presence of 455 nm visible light which is not cytoxic. <i>In situ</i> rheological measurements of PEG hydrogels formed by 455 nm light were performed to study the effect of PEG monomer and LAP concentrations as well as light intensity on gelation time and storage modulus. The storage modulus can be tuned for G’ values ranging from 400 – 10,000 Pa within 5 minutes. Additionally, bulk hydrogel formation, off the rheometer, was done using a 455 nm LED lamp from THOR labs. Swollen modulus rheological measurements were performed indicating hydrogels with less stiff mechanical properties, G’ ranging from 300-5,000 Pa. Additionally, cell experiments were performed to examine cell viability and culture in visible light-formed PEG hydrogels. These results indicate visible light can be used to form photoiniated hydrogels enabling less cytotoxic gel formation.

Visible light photoinitiation of poly(ethylene) glycol hydrogels

254th National Meeting (2017)

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