Navigating the mysterious world of nano-medicine

A Fantastic Voyage

Most discussions of the future of medicine tend to revolve around genetic manipulation, personalised pharmaceuticals, and putting off death as long as possible.

Yet the work that's going on in research labs in Basel, Switzerland, home of two of the world's biggest drug companies isn't about any of that. Instead, they are building on atomic force microscopy (AFM) to image and study the smallest structures in the human body with a view to working at the molecular level: nanomedicine.

More the 1966 movie Fantastic Voyage, less the 1997 movie Gattaca or the reconstruction of an entire Supreme Being from a few cells of 1997's Fifth Element.

"The long-term goal is to draw one drop of blood and have it analysed in minutes at the bedside," said Patrick Hunziker, a doctor with the intensive care unit at University Hospital Basel. That sounds like Gattaca, in which parents chose the genetic makeup of their babies before conception and people punched in at work with a drop of blood for DNA identification.

Then Hunziker turns to AFM images of collagen fibers forming the plaques of atherosclerosis, which eventually kills more than 50 per cent of Europeans. Fantastic Voyage, after all; in fact, Hunziker includes a still from the movie among his slides.

The movie was silly enough in concept: a team of doctors and a submarine were shrunk to micrometer size by a miniaturising ray gun and injected into the bloodstream of a comatose patient to go turn a laser beam on a blood clot that needed to be removed from his brain. In one hour. Before the miniaturisation wore off. But the visual imagery of their journey through the human body was startling enough to make most viewers forget, at least temporarily, the many logical flaws.

The history of medicine is a long series of developments allowing doctors to see better and more clearly into the human body: X-rays, MRI scans. Now, the notion of being able to see all the way down to the molecular level promises much earlier detection and much finer control. A different technique, X-ray phase contrast imaging, passes X-rays (either from ordinary tubes or from a synchrotron) through a series of tiny gratings, or arrays of slits, and from builds a detailed, three-dimensional picture of soft tissues from the reflections at much finer resolutions than is possible today.

Christian David, explaining the technique at the Paul Scherrer Institute, predicts many applications: distinguishing semtex and cocaine from cheese and chocolate inside luggage, product inspection, and mammography. Also heart disease: looking at the heart using today's methods requires contrast dyes, which are almost immediately flushed out. This technique does not require dyes.

Nor does it produce the kind of tissue damage familiar from traditional X-rays. "Radiography needs tissue damage to get an image," he said. "Phase contrast does not require any photons to be absorbed. You look at the change in direction of the wave but don't need to deposit harmful energy."

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