Mission into the body of man! A fabulous adventure into the last frontier of man!" In 1966, these breathless blurbs promoted a novel called Fantastic Voyage, written by master of science fiction Isaac Asimov .

It was based on the screenplay of a movie with the same name, released that same year. The story was fantastic enough: four men and a woman—the voluptuous Raquel Welch—are miniaturised along with an atomic submarine and released into the blood stream of a man whose death could mean the destruction of the world. So, they journey through his carotid artery, destroy a blood clot in his brain—and, obviously, save him and the world.

The human body is indeed one of the last, great frontiers, a workplace incredibly more difficult than Asimov could ever imagine, as difficult to reach as the farthest reaches of space.

Only last month, a diverse group of scientists from the Indian Institute of Science (IISc), Bangalore, announced in the journal Nano Letters that they had completed the first successful voyage of a super-tiny propeller or corkscrew—in scientific terms, a nanomotor—through blood. This comes on the heels of an effort, reported in February by a team at the University of Pennsylvania in the US, of nanomotors propelled by ultrasonic waves through live human cells and steered, as in Bangalore, with magnets.

The IISc team’s hope for the near future is to use the screws to deliver medicines that can kill cancer cells, a specific therapy that will hopefully be far less harmful and indiscriminate than terribly painful chemotherapy that destroys both good cells and bad.

Moving a nanomotor through blood or any living tissue is much more difficult than it sounds. In a cool, sterile laboratory at IISc’s Centre for Nano Science and Engineering, Ph.D student Arijit Ghosh reveals under a microscope how one of these screws—pulled along by a ring of external magnets—is propelled through water: straight, true and fast. His teacher and the man responsible for these experiments, physicist Ambarish Ghosh, 40, shows Mint a film of the same screw in blood. It weaves, bumps and bobs slowly and—there is no other word for this—drunkenly through a thickly packed ocean of blood cells.

When asked about the drunken trajectory, Ambarish Ghosh, a clean-shaven, good-humoured man, smiles and says: “Someone asked me, ‘Was it a weekend when you guys did this experiment’?"

The problem with running anything through blood is that it is five times thicker than water, highly corrosive and the screws in question are invisible to the naked eye. The largest of the screws, made of glass and manufactured at Ambarish Ghosh’s laboratory, is 5-microns long. It would take 12 screws, laid end to end, to bridge the width of a human hair.

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