MOF-derived magnetic Co@porous carbon as a direction-controlled micromotor for drug delivery

In recent years, self-propelled micromotors have attracted great attention due to their intelligent properties. To obtain a bubble-propelled micromotor, additional catalysts are required, which are usually expensive, toxic, and unstable, and lead to uncontrolled motion. To overcome these limits, ZIF-67, as a kind of MOF material, was chosen as a micromotor precursor; porous carbon decorated with magnetic Co nanocomposites (Co@PCs) could be obtained via an annealing process involving ZIF-67. These Co@PCs were used as micromotors for drug delivery, and were mass-producible, stable, and biocompatible. Due to the presence of magnetic Co, their motion could be controlled in a magnetic field. Co@PCs carbonized at 600 °C were self-propelled at a speed of 27.68 μm s−1, which corresponded to a relative speed of about 7.92 body-lengths s−1 at a fuel concentration of 5% with a lifetime of about 60 minutes. Furthermore, Co@PCs could be used as nanocarriers for the loading and release of the anticancer drug doxorubicin.