Biomedical engineers find active particles swim against the current

Researchers at Penn State are beginning to understand the behavior of so-called "active" particles, which, if controlled, has potential implications for smart 3D printing and engineered drug delivery systems. The particles – which can be biological but, in this case, are cylindrical platinum-gold nanorods smaller than a red blood cell – flow in a fluid through a micro-channel into a tapered nozzle. Once collected there, they can be used in additive manufacturing to 3D-print objects or to deliver therapeutics directly to cells.