Self-Propelled Tubular Micromotors Powered by Hydrogen Bubbles under Mild Conditions: A Major Step toward Biological...

Polymer-based tubular micromotors, featuring an inner layer of Pt nanoparticles (PtNPs), exhibit vigorous propulsion by emitting H₂ bubbles in an aqueous ammonia borane (NH₃BH₃) solution. The hydrolysis of NH₃BH₃ on the PtNPs facilitates the continuous release of H₂ gas from the open-end terminus, driving its forward movement. Unlike conventional O₂ bubbles' systems that rely on hydrogen peroxide (H₂O₂) as fuel, these micromotors can operate in the presence of live cells within the NH₃BH₃ medium. Consequently, micromotors functionalized with the lectin concanavalin A demonstrate the capability to capture and release Escherichia coli (E. coli) without inducing cell death. Remaining bacteria can be detected by using standard culture techniques. Conversely, micromotors coated with TiO₂ nanoparticles enable photosterilization of E. coli without fuel-induced damage. The self-stirring motion of the tubes enhances both bacterial capture and sterilization efficiency. These advancements obviate the necessity for H₂O₂ as a fuel source, and pave the way for the applications of micromotors in biological contexts.