A Macrophage-Magnesium Hybrid Biomotor: Fabrication and Characterization

Magnesium (Mg)-based micromotors are combined with live macrophage (M phi) cells to create a unique M phi-Mg biohybrid motor system. The resulting biomotors possess rapid propulsion ability stemming from the Mg micromotors and the biological functions provided by the live M phi cell. To prepare the biohybrid motors, Mg microparticles coated with titanium dioxide and poly(l-lysine) (PLL) layers are incubated with live M phi s at low temperature. The formation of such biohybrid motors depends on the relative size of the M phi s and Mg particles, with the M phi swallowing up Mg particles smaller than 5 mu m. The experimental results and numerical simulations demonstrate that the motion of M phi-Mg motors is determined by the size of the Mg micromotor core and the position of the M phi during the attachment process. The M phi-Mg motors also perform biological functions related to free M phi s such as endotoxin neutralization. Cell membrane staining and toxin neutralization studies confirm that the M phi s maintain their viability and functionality (e.g., endotoxin neutralization) after binding to the Mg micromotors. This new M phi-Mg motor design can be expanded to different types of living cells to fulfill diverse biological tasks.