Photoresponsive Gelation of Four-Armed Poly(ethylene glycol) with Photodimerizable Groups

Standard hydrogels prepared by free radical polymerization (FRP) have heterogeneous structures with a wide mesh size distribution, which affect their mechanical and separation properties. Recent research has identified four-armed poly(ethylene glycol) (tetra-PEG) as a solution to this problem. tetra-PEG gels with a homogeneous network can be prepared and applied as high-strength gels and cell-culture substrates by reacting two types of tetra-PEG with different reactive groups at the ends. In this study, we report a photoresponsive tetra-PEG that undergoes a phase transition from a sol to a gel state in response to light. tetra-PEGs containing cinnamoyl and maleimide groups at the ends of the four-armed chains were found to gel when exposed to light. The effects of polymer concentration and light irradiation time on the gelation of tetra-PEG containing photodimerization groups were investigated. The results showed that the elastic modulus of the gel increased with the increase in the light irradiation time.

Automated summary

In this study, a photoresponsive tetra-PEG gel that undergoes a phase transition from a sol to a gel state in response to light is reported. The gelation of the tetra-PEG containing photodimerization groups was investigated by varying the polymer concentration and light irradiation time, showing that the elastic modulus of the gel increases with the increase in light irradiation time.