Rapidly in situ forming adhesive hydrogel based on a PEG-maleimide modified polypeptide through Michael addition

Polyethylene glycol-maleimide modified epsilon-polylysine (EPL-PEG-MAL) with a unique comb-shaped structure was designed and used as a novel crosslinker for thiolated chitosan (CSS). Novel polysaccharide/polypeptide bionic hydrogels based on CSS and EPL-PEG-MAL could form rapidly in situ within 1 min via Michael addition under physiological conditions. Rheological studies showed that introduction of PEG can dramatically improve the storage modulus (G') of the hydrogels and the optimal hydrogel system showed superior G' of 1,614 Pa. The maximum adhesion strength reached 148 kPa, six times higher than that of fibrin glue. Cytotoxicity test indicated that the hydrogel is nontoxic toward growth of L929 cells. Gelation time, swelling ratio, storage modulus and adhesion strength of the hydrogels can be modulated by the content of PEG-maleimide, CSS concentration and molar ratio of maleimide group to thiol group. Benefiting from the fast gelation behaviors, desirable mechanical properties, relatively high adhesive performance and no cytotoxicity, these hydrogels have the potential applications as promising biomaterials for tissue adhesion and sealing.