Fig. 1

Synthesis and characterization of drug-loaded Mg-based micromotors. a Schematic preparation of the micromotors: Mg microparticles dispersion over a glass slide, TiO₂ atomic layer deposition (ALD) over the Mg microparticles, drug-loaded PLGA deposition over the Mg-TiO₂ microparticles, and Chitosan polymer deposition over the Mg-TiO₂-PLGA microparticles. b Schematic of in vivo propulsion and drug delivery of the Mg-based micromotors in a mouse stomach. c Time-lapse images (2 min intervals, taken from Supplementary Movie 3) of the propulsion of the drug-loaded Mg-based micromotors in simulated gastric fluid (pH ~1.3). d Schematic dissection of a drug-loaded micromotor consisting of a Mg core, a TiO₂ shell coating, a drug-loaded PLGA layer, and a chitosan layer. e Scanning electron microscopy (SEM) image of a drug-loaded Mg-based micromotor. f, g Energy-dispersive X-ray spectroscopy (EDX) images illustrating the distribution of f magnesium and g titanium in the micromotor. h–k Microscopy images of dye-loaded Mg-based micromotor: h optical image and fluorescence images showing the dye-loaded Mg-based micromotors in the i DiD channel (PLGA layer), j FITC channel (chitosan layer), along with an overlay of the two channels k