Advances in ultrasound-responsive hydrogels for biomedical applications

Various intelligent hydrogels have been developed for biomedical applications because they can achieve multiple, variable, controllable and reversible changes in their shape and properties in a spatial and temporal manner, thus greatly adapting to the complex application environments in vitro and in vivo. Among them, ultrasound-responsive hydrogels, as a new class of intelligent hydrogels, have shown irreplaceable application prospects due to their non-invasive, safe, controllable and economical response characteristics. In this review, we summarize the recent advances in ultrasound-responsive hydrogels for biomedical applications. The mechanism and performance of ultrasound-responsive hydrogels in the applications of ultrasound imaging, on-demand drug delivery and shape-memory are presented in detail, respectively, followed by the discussion of the challenges and prospects. The purpose of this review is to provide reference for the interaction between hydrogels and ultrasound for biomedical applications.