Would you like to see how the da Vinci surgical robot works? If so, Google "YouTube da Vinci suturing a grape." With remarkable dexterity, the task is done inside a bottle.

Today, surgical robots perform relatively "simple" procedures like mitral valve repairs to "heroic" resections, are suited to kidney transplants, and particularly apt for newborn and children. Recent innovations in surgical robotics include improving touch sensitivity, and magnetic resonance guided procedures in the brain, but the idea of an autonomous machine is not far-fetched.

In one clinical experiment, artificial intelligence provided guidance for unassisted robotic surgery to ablate arrhythmia-causing heart muscle. This was one of ten thousand procedures the machine could carry out on its own.

Remarkable as surgical robots are, there's another genre—microbots and nanobots—which bring to mind the 1966 sci-fi movie "Fantastic Voyage." In that film, a microscopic submarine swims through the blood stream, intending to break up a blood clot in a Soviet scientist's brain. It faces a number of problems in its propulsion, positioning, means of dissolving the clot, clearing the debris, and exiting the body. These are the same issues now facing MEMS (microelectrical-mechanical systems) and nanotechnology engineers as they envision doing the same thing, along with targeting tumors in areas of the brain which are surgically inaccessible, alleviating hydrocephalus, clearing arteriosclerotic plaque from artery walls and other applications.

Design considerations begin with a choice between wired or autonomous robots. Wired machines resemble laparoscopic devices that are now inserted through the femoral artery and "snaked" into the heart. Conceivably, the control wire could include a tube for evacuating plaque or clot debris in the cardiovascular system. Autonomous machines raise a higher magnitude of considerations, especially for working deep inside the brain, though engineering choices already exist. Tiny electric motors are capable of turning a propeller; piezoelectric membranes can generate ultrasound positioning signals; a pulsed laser diode could sense tumor tissue location; laser diode, ultrasound, or infrared heating can ablate tumors; magnetic induction from outside the body can provide power; and a small incision could retrieve the bot after its work was done. Short of clearing a brain tumor in this way, breaking up gallstones or kidney stones are possible early steps. While this concept remains on the edge of science fiction, reality is looking ever more possible.

Researchers at the Nano Robotics Lab of the Ecole Polytechnic de Montreal designed a microcarrier for drug delivery and used an MRI machine to move the device into rabbit livers. Researchers in Germany have made microtube carrier of titanium and platinum, also MRI guided and capable of drug delivery, but with added propulsion from onboard hydrogen peroxide reacting with the platinum to produce a force of microbubbles. Drexel University bioengineers are experimenting with iron oxide beads rotating in a spinning magnetic field with an attached micro drill head for clot busting.

According to one of these scientists, ". . . . a real-life fantastic voyage is just beginning."