Single component Pluronic F127-lipoic acid hydrogels with self-healing and multi-responsive properties

Herein, Pluronic F127 (PEO99-PPO65-PEO99) end functionalized with α-lipoic acid (LA) (F127-LA) was synthesized and used for preparation of "single-component, multi-responsive" hydrogels through the photo cross-linking of LA components. The F127-LA hydrogels not only possessed thermo- and reduction- double responsiveness, but also demonstrated self-healing properties under UV irradiation due to the existence of dynamic disulfide bonds. The rheological and mechanical properties of the hydrogels can be adjusted by their concentration. The F127-LA hydrogels presented a swelling ratio decrease from 25 °C to 37 °C due to a lower critical solution temperature (LCST)-type thermo-responsive volume phase transition. The bovine serum albumin (BSA) was loaded into F127-LA hydrogels, and their drug release behavior can be regulated by surrounding temperature and reducing agent concentration. The volume shrinkage of the hydrogels promoted the sustained release of BSA above volume phase transition temperature. Cytocompatibility assay of L929 mouse fibroblasts showed that cellular metabolic activity were merely affected by F127-LA, even at concentrations up to 1000 mg L−1. This study thus provided a very promising route for the preparation of multifunctional hydrogels.