Switching from Chemical to Electrical Micromotor Propulsion across a Gradient of Gastric Fluid via Magnetic Rolling.

To address and extend the finite lifetime of Mg-based micromotors due to the depletion of the engine (Mg-core), we examine electric fields, along with previously studied magnetic fields, to create a triple-engine hybrid micromotor for driving these micromotors. Electric fields are a facile energy source that is not limited in its operation time and can dynamically tune the micromotor mobility by simply changing the frequency and amplitude of the field. Moreover, the same electrical fields can be used for cell trapping and transport as well as drug delivery.

Electrical Propulsion and Cargo Transport of Microbowl Shaped Janus Particles.

Herein the effective electrical propulsion, cargo trapping, and transport capabilities of microbowl-shaped Janus particles (JPs) are demonstrated and evaluated. These active JPs are made by deposition of Au and Ti layers onto sacrificial spherical polystyrene particles, followed by oxidation of the Ti to TiO . In contrast to the commonly studied spherical JP, the dual broken symmetry of both geometrical and electrical properties of the microbowl renders a strong dependence of its mobility and cargo loading on the order of the layering of Au and TiO .