Navigating the mysterious world of nano-medicine

A Fantastic Voyage

That lack of damage should be a selling point. "The question is, can we get this into hospitals?" he said. The technique needs more work with ordinary X-ray tubes instead of PSI's near-by synchrotron, the Swiss Light Source, and doctors and technicians need to be convinced. Medical equipment manufacturers seem the most likely conduit.

Martin Stoltz, a doctor at Biozentrum is exercised by a completely different question: "What's the point of living past 130," he said, "if for the last 20 years of your life you can't get out of bed because your joints don't work?" His target is arthritis, which is on the rise everywhere, and his tool is AFM, which his team has developed into a technique they call Arthroscan, which he predicts will be the most widely used detection device worldwide by 2015.

On the nanometer scale, he said, the difference in elasticity between a knee's healthy cartilage and cartilage showing early signs of osteoarthritis is startling. In his image, the first looked like loosely scattered strands of spaghetti, the second like twigs forming a bird's nest. Today's MRIs give only limited information and "No early detection," he said. "Precise diagnosis at the nanometer scale will enable effective healing of cartilage disease."

A third approach is sensors built of tiny cantilevers that can detect microorganisms in 90 minutes rather than the 20 hours it takes a colony to grow to sufficient size in a Petri dish. Coating the cantilevers with antibodies, said Christoph Gerber, allows multiple protein detection. The personalised medicine of so many mass media stories could be enabled by this type of nanomechanical sensor.

All of these ideas – and also those of cancer researcher Marija Plodinec – converge on the notion of being able to detect warning signals at the molecular level and to treat individual cells before they can cause too much damage. Nanocarriers made of polymers of the kind already safely in use in the human body could carry drugs that first detect a condition and then turn themselves on to treat only the target cells, an approach Hunziker called "theragnostics".

Hunziker himself has had some good results, but they're not ready for clinical trials – and when they are, probably the atherosclerosis patients he sees most won't be first in line. Typically, very new treatments, after animal testing, are most likely to be tried on humans whose chances for survival are bad already. Cancer, therefore, is a more likely first target.

He almost sounds wistful, therefore, when he says: "I would like to cure atherosclerosis by the time of my retirement." He is 43.

Busting up atherosclerosis plaques might be more similar to busting up a clot, but Hunziker's work's real similarity to Fantastic Voyage is in the emphasis on making things – drugs, devices – small enough to interact on the same scale as human cells. As Hunziker says, there is a fundamental size mismatch between today's microscopic tools and any attempt to fix problems at the cellular level – and the cellular level, as Stoltz noted, is where all diseases start.

One must hope, though, that no one uses a miniaturising ray to get to that level. Because no one ever explained, at the end of Fantastic Voyage, why the atoms that made up the submarine, abandoned in a blood vessel, didn't explode the patient when they returned to full size. ®

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