A Trinity College Dublin researcher has developed a test that can deliver swift results in tests for bugs such as malaria and swine flu
IN THE FUTURE, testing children for immunity to malaria could be a much faster and less traumatic process than at present. Miniature technology developed at Trinity College Dublin can reduce the amount of blood needed to just a pinprick.
The new technique will give results within minutes and allow many people to be checked in a short time.
When testing children it is not possible to get large blood samples, and “when the samples you get are really tiny you need to adapt your ”, explains Prof Martin Hegner, who heads the project.
Tiny silicon springboards are at the heart of this technology, and they are built to a remarkable scale. The width of each springboard measures no more than the thickness of two sheets of paper.
The rapid detection method works by vibrating the springboards and then recording how they move. But the range of movement monitored is incredibly small, measured in just millionths of a millimetre.
The boards will move differently depending on what is attached to them, says Hegner. The new technique is so sensitive that very small changes can be detected. This would be a great advantage when testing for malaria immunity.
Malaria parasites gain entry to red blood cells and live in them where they can hide from the immune system, explains Hegner. The aim of any malaria vaccine is to block entry into the cells so that the “parasites cannot find any entry point”, he says. People with immunity have cells that naturally block the entry of these parasites.
Tests are planned at the Centre for Research on Adaptive Nano-structures and Nanodevices (Crann), Trinity College Dublin, to establish how the silicon technology could be used to quickly confirm natural immunity or immunity delivered by the vaccine.
The springboards are already being used to detect other organisms, bacteria and harmless viruses. The springboards are coated with substances that attract and hold these organisms. In the case of malaria, the springboards would be coated in membranes taken from red blood cells.
The movement of the boards would then be monitored. If the parasites “are docking to the membrane”, changes in the board movement would be detected. “The docking process is what we measure,” Hegner says.
Experts on a wide range of subjects are needed to develop the technology. Materials used at the heart of desktop computers are being combined with know-how from physics and biology.
Scientists from many backgrounds have been brought together under one roof at Crann. To make this project work, it is “crucial that they are within a short walking distance”, Hegner says.
The project, supported by the Science Foundation Ireland, also makes use of a link with the Swiss Tropical Institute, Basle, Switzerland.
The great advantage of this approach is that it could also be used in the diagnosis of the swine flu virus, Parkinson’s disease, and many others. The molecules are different, but the detection method stays the same.
We have “developed proof of principle for virus detection”, Hegner says. The springboard technique takes minutes to complete and is “more sensitive than current diagnostics”.
Current diagnosis methods use colour and light labels which allow the virus to be seen. This is “like attaching a light bulb to each virus”, Hegner says. If the labelling doesn’t work, the virus will go unnoticed.
The silicon springboard technique does not suffer from this problem. No extra chemical additives are needed and the method is quick and accurate. The screening of large numbers of patient samples in a flu outbreak is one possible application.
Checks for contamination in sterile products could also be done in this way. In this case the springboards would be coated with nutrients that encourage the growth of bacteria.
Even a very small amount of bacterial growth can be detected as changes in springboard movement and these will show up within a couple of hours. By contrast, current methods of incubation and inspection by eye can take 24 hours.
Alison Jones is a British Science Association media fellow on placement with The Irish Times