A postgraduate student who developed a chemical sensor to measure copper levels in the body has won the RIA 2005 Young Chemist of the Year competition.
Dr Andrew Harte, who completed his PhD thesis at Trinity College Dublin, was presented with a John Coen bronze sculpture and a cheque for €1,000 earlier this week at the Royal Irish Academy in Dublin.
PhD candidates who undertake the challenge are asked to write a simple 1,000 word explanation of their doctoral research, with the clearest, best written report winning the award. The competition is organised by the RIA with the support of The Irish Times and AGB Scientific.
Copper is essential for health, but too much or too little can cause diseases such as Menkes and Wilkins diseases. "There are numerous diseases that are caused by a deficiency or excess of copper in the blood," says Harte.
Measuring copper levels requires specialised equipment and can only be done in the lab. "At the moment it is done using expensive machinery."
His PhD research with supervisor, Prof Thorri Gunnlaugsson, involved the development of a novel chemical sensor that could detect and measure trace copper levels in the blood. To accomplish this they turned to an exotic group of elements on the Periodic Table, the Lanthanide Series.
"The work was focused on using lanthanide ions wrapped up in an organic scaffold to measure copper and also aspirin levels," Harte explains. Both are difficult to measure, and while copper levels are linked to disease, high aspirin levels can cause stomach bleeding and ulcers.
Harte and his supervisor decided to exploit the natural luminescence of elements in the Lanthanide Series. They chose Europium to test for copper and Terbium to measure aspirin.
"We used them for their light emitting properties," he says. "Under certain circumstances they will emit a light signal at long wavelengths in the 580 to 750 nanometre range. That long wavelength is quite important because it gives you a much better signal for body tissues," Harte explains.
The twin challenge was to get them to luminesce at all and to luminesce in a way that could be interpreted and so provide information. The researchers developed a particularly elegant way to achieve this in the case of their copper sensor by developing a chemical "antenna" that could both encourage the Europium to luminesce and also provide a way to measure copper.
It is difficult to force lanthanides to luminesce directly so Harte built a chemical antenna, made of three benzene rings, nitrogens and a "spacer" that could connect to the Europium.
The antenna channels light photons into the Europium causing it to luminesce, but the antenna also became the docking site that could detect the presence of copper.
"The beauty of it is we used the antenna as the receptor so it automatically binds the copper and that bonding in turn modulates the light being emitted by the Europium," Harte explains.
If copper levels are low the antenna readily channels photons into the Europium, boosting luminescence. If copper is present and binds to the antenna, this blocks the photons, switching off the light and stopping luminescence. The researchers developed two such chemical sensors for copper and for aspirin as part of the project, which was funded by Enterprise Ireland and by Trinity College.
Harte believes the sensors could be developed into inexpensive and highly portable test kits. "It definitely could be adjusted to work as a test, but I did all of my work in solution," he said.
• Details of the Young Chemist of the Year competition and how to apply are available at www.ria.ie
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