Magic silver bullets

Minute particles of the precious metal could help revolutionise medicine, writes Berni Dwan

Minute particles of the precious metal could help revolutionise medicine, writes Berni Dwan

Richard Feynman was so right, in his prophetic 1959 talk to the American Physical Society, when he said there was "plenty of room at the bottom". Alluding to what we now know as nanotechnology, he described manipulating things on a small scale, predicting that such developments would have plenty of technical applications.

You only have to go to the physics department at Trinity College in Dublin to see a practical vindication of Feynman's prediction. Prof Werner Blau, the head of the department, and his nanotechnology research team are involved in a range of innovative projects.

One involves the use of nanoparticles, which are small enough to enter cells, to revolutionise medical disciplines such as diagnostics, drug delivery and cancer treatment. Prof Blau's project is under way at the Materials Ireland research centre, with Dr Margaret Brennan leading the work. It involves a collaboration with Prof John Kelly and Áine Whelan of Trinity's chemistry department.

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The nanoparticles in question are silver; what makes them so special is that they can change colour. Dr Brennan realised they could be used as biosensing indicators, for detecting meningitis, hepatitis or rheumatoid arthritis.

"The principal of our detection device involves attaching specific biodetector molecules to nanoparticles, which interact on coming into contact with the target molecule. The nanoparticle then issues a signal that detection has occurred," says Dr Brennan.

Using the nanoparticles' colour-change feature provides an important short cut for medical diagnostics. You attach to the nanoparticle components of the disease organism that you want to detect, such as meningitis. Then you add a fluid sample from the patient.

If the person has been challenged by the disease and raised antibodies against it, these will react with the nanoparticle and the meningitis component it carries. This will cause a colour change: confirmation that the disease is present.

"What we hope to develop is an easy-to-use rapid-detection diagnostic kit for in vitro use," says Dr Brennan. "The kit would be used for the detection of a variety of species, including disease pathogens and food-borne pathogens."

This would allow GPs to take blood or urine samples and obtain immediate results. They would no longer have to send samples to laboratories and wait days for the results. This would be a tremendous advantage when diagnosing meningitis, when it is often necessary to begin treatment before tests confirming the disease are complete.

"The next stage will be to develop the biosensor together with an Irish company producing diagnostic kits, and we are looking to meet interested companies," says Dr Brennan.