Over the past decade, researchers have been developing microscopic and nano-scale devices that can be used in medicine to attack tumors, target specific metabolic processes, and help diagnose disease. Overall, the most common method of reaching specific kinds of cells is to attach molecules to the man-made particles that bind to surface receptors on target cells, and there have been other approaches taken as well. Now researchers from MIT have reported on an entirely new method for microscopic particles to travel through live tissue while searching for high concentrations of specific kinds of cells.
They call their approach “tribotaxis,” as in relating to friction and locomotion induced by an external force. The investigators combined two magnetic particles that roll over each other when subjected to a magnetic field. The surface of the particles reacts to higher friction, tumbling towards it. The higher friction is due to cell surfaces around the engineered particles having more biological receptors, and by using the magnetic field as a source of energy the particles move along the friction gradient. Changing which receptors the microparticles respond to will influence where they’re naturally drawn to.
Here’s an animation showing micro walkers tumbling along. Areas colored orange have greater friction:
Micro walkers tumbling across a surface, under the influence of a rotating magnetic field, until they find areas where friction is highest.
Article in Physical Review Letters: Artificial Tribotactic Microscopic Walkers: Walking Based on Friction Gradients…
Press statement by MIT: Microscopic “walkers” find their way across cell surfaces…