Precise delivery of therapeutic drugs into diseased tissue remains a challenge in a variety of cases. Tumors can be hard to seed with chemo agents, particularly when the blood flow is not favorable for delivery. Now, researchers at the Max Planck Institute for Intelligent Systems in Germany have developed microscopic drug delivery devices that can travel against the flow of blood. The new microrobots were inspired by leukocytes (white blood cells) that are naturally able to roll along the interior walls of blood vessels, and even move against the flow of the surrounding blood. However, while leukocytes are self-powered, the new devices rely on an external magnetic field to get them to their target. Having about the same size, shape, and locomotion capabilities as leukocytes, the microrobots feature a chamber that can be loaded with drugs and a surface to which antibodies can be attached. While a magnetic field can push the microrobots toward their destination, the antibodies help to bring each device precisely to where it is needed. Having built the microrobots, the researchers successfully tested them on mimics of blood vessels, using a magnetic field to roll them along the interior walls. Moreover, the team was also able to use the antibodies attached to the microrobots to guide the devices toward individual cancer cells where they dropped off their therapeutic cargo. Study in Science Robotics: Multifunctional surface microrollers for targeted cargo delivery in physiological blood flow Source
