Thermally tunable hydrogel crosslinking mediated by temperature sensitive liposome.

Hydrogel crosslinking by external stimuli is a versatile strategy to control and modulate hydrogel properties. Besides photonic energy, thermal energy is one of the most accessible external stimuli and widely applicable for many biomedical applications. However, conventional thermal crosslinking systems require a relatively high temperature (over 100 °C) to initiate covalent bond formation. To our knowledge, there has not been a thermally tunable hydrogel crosslinking system suitable for biological applications. This work demonstrates a unique approach to utilize temperature sensitive liposomes to control and modulate hydrogel crosslinking over mild temperature range (below 50 °C). Temperature sensitive liposomes were used to control the release of chemical crosslinkers by moderate temperature changes. The thermally controlled crosslinker release resulted in tunable mechanical and transport properties of the hydrogel. No significant inflammable response observed in the histology results ensured the biocompatibility of the liposome-mediated crosslinkable hydrogel. This work opens new opportunities to implement thermal energy system for control and modulate hydrogel properties.