The second device, also designed by Lee, uses a similar system of tiny polymer and iron oxide particles, although it relies on ribosomal RNA (rRNA) instead of DNA. The researchers developed bits of DNA designed to stick to pieces of rRNA commonly found many bacteria; other bits of DNA are used to target 13 dangerous diseases, including Strep, E. coli and methicillin-resistant Staphylococcus aureus (MRSA). Applying a magnetic field to the particles generates signals that differ depending on the kind of DNA they stick to.
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The devices performed as well or better than other laboratory tests and worked faster - results came in two to three hours, and both gadgets were able to pick up lower levels of bacterial exposure with smaller samples. On top of that, they could tell what strain of TB was present.
Both systems are some time away from commercialization. Hakho Lee, a physicist and co-author on both papers, said the big issue is making it robust enough for field conditions. "It should operate with a battery, in a lot of different temperature variations," he told Discovery News. "We want the device to be automatic, and we can't have any contamination [of the sample] or we'll get false positives." MGH is looking for partners to help develop the technology, he said.