Bioinspired micro-robot based on white blood cells

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny micro-robot that resembles a white blood cell traveling through the circulatory system. It has the shape, the size and the moving capabilities of leukocytes, and could perhaps revolutionize the minimally invasive treatment of illnesses.

Simulating a blood vessel in a laboratory setting, the team succeeded in magnetically steering the micro-roller through this dynamic and dense environment. The ball-shaped drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: Inside the body, there is no better access route to all tissues and organs than the circulatory system. It spans every cell, offering an ideal route for navigation.

The team took inspiration from white blood cells, the task force of the immune system, as they are the only motile cells in the blood stream. On their patrol to places where pathogens have invaded, they roll along the blood vessel walls, penetrating out of the blood vessel when they reach a trouble spot. The key to their motility is mainly due to substantially decreased flow velocity at the vessel walls.

Exploiting the same phenomenon, the scientists developed a micro-robot they can actively propel forward and navigate inside the blood vessels in physiological high-speed blood flow conditions thanks to its magnetic properties.