Research / 2020 / Article / Fig 1

Review Article

Requirement and Development of Hydrogel Micromotors towards Biomedical Applications

Figure 1

Fabrication of hydrogel micromotors using microfluidics. (a) Hydrogel microparticles with an aqueous core containing photocatalytic nanoparticles. Schematic illustration (I) and optical images of ZnO nanoparticles (II) and TiO2 nanoparticles (III) inside the capsule. Reproduced with permission from ref. [42], RSC 2020. (b) Hydrogel micromotors are fabricated using glass capillary-based microfluidics. Mechanical activation of hydrogel microcapsules by compression using metallic tweezers leaves holes/defects in the membrane of hydrogels (I). A schematic image of a hydrogel microcapsule containing catalytic nanoparticles in an aqueous core is shown. The process leads to a membrane rapture and nucleation/generation of an oxygen microbubble during the decomposition of hydrogen peroxide (II). Optical microscopy image sequences of an individual self-propelled microcapsule-based hydrogel micromotor (III). The force produced by a lateral capillary (Fc) is indicated using blue arrows, while the force (Fm) produced by the catalytic effect is indicated using the red arrow. The two forces are the main motive mechanisms of the hydrogel micromotor. The scale bar is 200 μm. Image is reproduced with permission from ref. [43], IOP 2019.