Requirement and Development of Hydrogel Micromotors towards Biomedical Applications

With controllable size,biocompatibility,porosity,injectability,responsivity,diffusion time,reaction,separation,permeation,and release of molecular species,hydrogel microparticles achieve multiple advantages over bulk hydrogels for specific biomedical procedures.Moreover,so far studies mostly concentrate on local responses of hydrogels to chemical and/or external stimuli,which significantly limit the scope of their applications.Tetherless micromotors are autonomous microdevices capable of converting local chemical energy or the energy of external fields into motive forces for self-propelled or externally powered/controlled motion.If hydrogels can be integrated with micromotors,their applicability can be significantly extended and can lead to fully controllable responsive chemomechanical biomicromachines.However,to achieve these challenging goals,biocompatibility,biodegradability,and motive mechanisms of hydrogel micromotors need to be simultaneously integrated.This review summarizes recent achievements in the field of micromotors and hydrogels and proposes next steps required for the development of hydrogel micromotors,which become increasingly important for in vivo and in vitro bioapplications.

Atomic layer deposition-induced integration of N-doped carbon particles on carbon foam for flexible supercapacitor

Flexible devices have attracted abundant attention in energy storage systems.In this paper,we presented a novel approach for fabricating flexible supercapacitor based on metal organic frameworks-derived material.In this approach,a uniform zeolitic imidazolate frameworks-8 layer with a high mass loading was deposited on a flexible carbon foam(CF)skeleton efficiently by the induction of a uniform ZnO nanomembrane prepared via an atomic layer deposition technique.A flexible N-doped carbon particle-carbon foam(N-CP-CF)composite with a hierarchically porous structure and a large specific surface area(i.e.,538 m^(2) g^(-1))was obtained in a subsequent pyrolysis process.The resultant materials have the excellent electrochemical performance(i.e.,a high specific capacitance of 300 F g^(-1) and a high energy density of 20.8 W h kg^(-1)).The N-CP-CF composite can provide a stable capacitance(i.e.,250 F g^(-1))and an energy density(i.e.,17.36 W h kg^(-1))under large deformation(25% of original thickness).This work could propose a promising strategy in fabrication of flexible electrode with a large potential towards energy storage applications in the future.