Micro-submarine in artery. Conceptual coloured scanning electron micrograph of a micro-submarine (blue/grey) in a human artery. This tiny submarine was made by computer-guided lasers. Laser light caused an acrylic liquid to polymerise, building up the submarine in layers 10 micrometres thick. Tiny nanorobots such as this could be used for detecting and repairing defects in the human body. Powered by a small propeller, they could travel to sites of blockage or damage in blood vessels and repair them from within, restoring blood flow. This submarine was made by microTEC of Duisburg, Germany. Magnification: x12 at 6x7cm size.