摘要
The rapid development of medical micromotors draws a beautiful blueprint for the noninvasive or minimally invasive diagnosis and therapy.By combining stimuli-sensitive hydrogel materials,micromotors are bestowed with new characteristics such as stimuli-responsive shape transformation/morphing.excellent biocompatibility and biodegradability,and drug loading ability.Actuated by chemical fuels or external fields(eg,magnetic field,ultrasound,light,and electric field),hydrogel-based stimuli-responsive(HBSR)micromotors can be utilized to load therapeutic agents into the hydrogel networks or directly grip the target cargos(eg.,drug-loaded partides,cells,and thrombus),transport them to sites of interest(e.g.,tumor area and diseased tissues),and unload the cargos or execute a specific task(e.g.,cell capture,targeted sampling,and removal of blood dots)in response to a stimulus(eg.,change of temperature,pH,ion strength,and chemicals)in the physiological environment.The high flexibility,adaptive capacity,and shape morphing property enable the H BSR micromotors to complete specific medical tasks in complex physiological scenarios,especially in confined,hard to-reach tissues,and vessels of the body.Herein,this review summarizes the current progress in hydrogel-based medical micromotors with stimuli responsiveness.The thermo-responsive,photothermal-responsive,magnetocaloric-responsive,pH-responsive,ionic strength-responsive,and chemoresponsive micromotors are discussed in detail.Finally,curent challenges and future perspectives for the development of HBSR micromotors in the biomedical field are discussed.
基金
support from the National Key R&D Program of China(2020YFC2007300)
the National Natural Science Foundation of China(U20A20388)
support from the Beijing Institute of Technology Research Fund Program for Young Scholars(XSQD-202123003)
support from the Natu-ral Science Foundation of Jiangsu Province of China(BK20190809)
support from the Beijing Institute of Technology Teli Young Fellow Program(33012222218).