Smart bandage guides repairs

A TECHNIQUE to guide the cells of regrowing tendons and bones has been patented by scientists at Glasgow University, writes Nuala Moran.

It will be used in smart bandages, made of plastics compatible with the body.

These would be used to repair a broken tendon by aligning the two ends together and acting like a splint. The bandage will then guide growing tendon cells not only in the right direction, but also to regrow the correct cross-section. The bandage will biodegrade as the tendon cells grow to leave a completely new section of tendon. Without guidance, the cells tend to grow aimlessly - often doubling back on themselves or growing in spirals. When tendons in the hands are repaired they can stick on surrounding structures and leave the hand in a fixed position.

This method of directing cells is the fruit of a collaboration between electronic engineers and biologists who are working on biological computers or neural networks. Two professors, Adam Curtis and Chris Wilkinson, have created surfaces made of biocompatible materials that can support growing nerve cells.

The surface has tiny grooves, thinner than a human hair, etched on it, which direct the growth of the cells. The researchers have used this to create a primitive biocircuit that can transmit electrical signals.

The patent covers the technique of embossing the correct microstructure on to flexible biodegradable bandages. Glasgow University is working with Ethicon, a sutures manufacturer (and subsidiary of Johnson & Johnson), to develop the bandages. To date, the technique has been tested only in laboratory cultures, and Professor Curtis is now hoping to do animal trials.

He says this development is an important first stage in the long-term goal of cellular engineering, aimed at developing methods of encouraging the body to perform its own tissue reconstruction rather than implanting man-made devices. 'The eventual aim is to act like a DIY store, supplying the parts the body needs to rebuild tissues such as tendons or bones.' For example, he suggests that eventually such guidance systems could provide templates for hip replacements.

Professor Curtis says it may in future be possible to make hip replacements of biodegradable plastics incorporating the guidance system. This would provide support while the bone gradually regenerated to take the place of the implant, which would need to biodegrade at the right rate.

Meanwhile, the biocircuits developed by the Glasgow scientists are forming the basis of a non-invasive method of studying signalling between cells and how cells process information. This research will be applied both to computer design and cellular engineering.

Professor Wilkinson says that although his team has succeeded in producing a biocircuit, the constraints are likely to prevent anyone from using the technique to build biological computers - they would have to be kept in solution at a constant 37C and fed a substrate to keep them growing. 'They would also be slow and error-prone,' he says.

However, the findings about cell signalling mechanisms could be incorporated into silicon chip design to improve the performance of computers.

Biocircuits would also be powerful diagnostic tools for studing the effects of drugs. The signals going through a cell could be measured before and after drug administration, giving a precise measurement of the drug's effect on cell signalling and hence cell function.

(Photograph omitted)