Fantastic voyage

Micro-subs will deliver drugs to a specific site in the body

Published: Sunday 15 January 2006

scientists in the us have developed self-assembling microcontainers, as tiny as a speck of dust, which could be used to deliver medicine inside the body and also for cell therapy.

By adopting the same thin film deposition techniques as are used to make microelectronic circuits, David H Gracias and colleagues at the Johns Hopkins University produced a flat pattern of six squares (made of copper or nickel), in a shape resembling a cross. Small openings were etched into each of the squares to allow medicine or therapeutic cells to pass through the microcontainers.

The researchers then used solder to form hinges along the edges between adjoining squares. On heating the flat shapes in a laboratory solution, the metallic hinges melted and each pair of adjoining squares came together like a swinging door, producing a perforated cube. When the solution was cooled, the solder hardened again, and the containers remained in their box-like shape. The study was published in the December 2005 issue of Biomedical Microdevices (Vol 7, No 4).

"The self-assembly technique allows us to make a large number of these microcontainers at the same time and at a relatively low cost," said Gracias in a press release issued by the university. The tiny cubes are coated with a layer of gold, so that they do not pose toxicity problems within the body.

The microcontainers are yet to be tested in humans or animals. But researcher Barjor Gimi and colleagues (also from the same university) have shown that magnetic resonance imaging, commonly called mri , could be used to locate and track the microcontainers as they moved through a sealed fluid channel. Some of the micro-cubes (those made mostly of nickel) are magnetic, and the researchers believe that it should be possible to guide them directly to the site of an illness or injury.

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