Chemical reaction dependency, magnetic field and surfactant effects on the propulsion of disk‐like micromotor and its application for E. coli transportation

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In this article, a miniature micromotor comprising of gold, nickel, and platinum is proposed. Herein, platinum acting as a chemical catalyst stimulates hydrogen peroxide to decompose into water and oxygen bubbles separated from the surface, which conversely produces a recoil force to drive the gold‐nickel‐platinum micromotor propelling forward. The micromotor is synthesized by a layer‐by‐layer coating strategy based on the micro‐electro‐mechanical systems technology. The propulsion of the as‐synthesized micromotor is experimentally conducted in diluted hydrogen peroxide both with and without the presence of external magnetic field, disclosing that oxygen bubbles are produced and separated from the platinum surface. Moreover, the results show that the speed of the gold‐nickel‐platinum micromotor is larger at higher hydrogen peroxide concentration, and the micromotor is able to move forward in an either linear or circular trajectory depending on the separation site of oxygen bubbles, the propulsion path of the micromotor can be manipulated by external magnetic field as well. Hence, the propulsion of the micromotor is chemical reaction‐ and magnetic field‐dependent. In addition, the surfactant effect on the propulsion of micromotor and its application for E. coli transportation are investigated.