Dual Enzyme-Triggered In Situ Crosslinkable Gelatin Hydrogels for Artificial Cellular Microenvironments

Horseradish peroxidase (HRP) and hydrogen peroxide (H₂ O₂ )-mediated crosslinking reaction has become an attractive method to create in situ forming hydrogels. While the crosslinking system has been widely utilized, there are certain issues require improvement to extend their biomedical applications, including creation of stiff hydrogels without compromising cytocompatibility due to initially high concentrations of H₂ O₂ . A gelatin-based hydrogels formed through a dual enzyme-mediated crosslinking reaction using HRP and glucose oxidase (GOx) as an H₂ O₂ -generating enzyme to gradually supply a radical source in HRP-mediated crosslinking reaction is reported. The physicochemical properties can be controlled by varying enzyme concentrations. Furthermore the hydrogel matrices provide 3D microenvironments for supporting the growth and spreading of human dermal fibroblasts with minimized cytotoxicity, despite the cells being encapsulated within stiff hydrogels. These hydrogels formed with HRP/GOx have great potential as artificial microenvironments for a wide range of biomedical applications.