Photo-curable, double-crosslinked, in situ-forming hydrogels based on oxidized hydroxypropyl cellulose

Chemoselective oxidation of oligo(hydroxypropyl)-substituted polysaccharides affords ketones at side chain termini, which readily condense to in situ-forming hydrogels with amine-containing polymers. This type of imine-crosslinked hydrogel displays several interesting and practically valuable properties including injectability, self-healing, tunable moduli, and ability to respond to multiple types of stimulus, so that these are promising materials for biomedical applications. As oligo(hydroxypropyl)-substituted polysaccharides are multi-functional and have the potential to be further chemically modified, a variety of useful motifs and interesting properties can be incorporated into these hydrogel systems. In this study, methacrylate groups were appended to oxidized hydroxypropyl cellulose (Ox-HPC) by esterification, conveying to the hydrogel the ability to be cured by exposure to ultraviolet (UV) radiation and reinforced by this second crosslinking mechanism. Hydrogel modulus was greatly enhanced (from 1800 Pa to 14 kPa) by UV curing. These hydrogels exhibit self-healing and injectability properties both before and after UV curing, suggesting that these materials have promise, including for 3D printing and biomedical applications. Overall, this work demonstrates synthesis, preparation, and photo-responsive properties of methacrylate-functionalized Ox-HPC/Chitosan hydrogels, broadening the family and utility of oligo(hydroxypropyl)-substituted, polysaccharide-based hydrogels. Graphic abstract UV-induced crosslinking of acrylated Ox-HPC/chitosan hydrogel.

Automated summary

Chemoselective oxidation of oligo(hydroxypropyl)-substituted polysaccharides results in ketones formation at side chain termini, which can readily form hydrogels in situ with amine-containing polymers. These hydrogels exhibit promising properties such as injectability, self-healing, tunable moduli, and responsiveness to various stimuli, making them potential materials for biomedical applications. By introducing methacrylate groups to the oxidized hydroxypropyl cellulose (Ox-HPC) through esterification, UV-induced crosslinking and reinforcement were achieved, significantly enhancing the modulus of the hydrogels. The hydrogels show self-healing and injectability properties both before and after UV curing, demonstrating potential for 3D printing and biomedical applications.