Description: We are developing a cell-free sensor that conditionally expresses a chromoprotein only in the presence of thallium. The metal ion detection is based on a DNAzyme that is cleaved in the presence of thallium. The released DNA strand activates a toehold switch regulated by the T7 promoter system, which will promote transcription of T3 and T7 RNA polymerases. The transcription of additional T7 RNA polymerase will amplify the signal from thallium. The T3 RNA polymerase will activate the expression of a chromoprotein. Our circuit will also incorporate a differential amplifier to remove noise from other heavy metals such as mercury. For the differential amplifier, a second DNAzyme with a greater affinity for other metals will be cleaved and produce a DNA strand complementary to that from the thallium DNAzyme. This will remove noise from other heavy metals that may also cleave the thallium DNAzyme.Early in the brainstorming process, our team wanted to develop a biosensor, since previous projects that hijacked glucometers and pregnancy tests sparked our interest. In deciding what to detect, we looked for analytes that were less widely studied and eventually decided upon thallium. Thallium, like lead and mercury, its neighbors on the periodic table, is toxic to humans. Because it has a similar atomic radius as potassium, thallium follows potassium pathways in the body. Thallium poisoning in low dosages results in hair loss and damage to the peripheral nervous system. In high doses, thallium is lethal. Thus, detection of thallium is important, especially in areas with industries that use thallium.We are also looking for collaborators. If you are interested, please contact us at pitt.igem.2016@gmail.com. We look forward to an exciting summer!
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Year: 2016Visit Wiki
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Updated at: 8/9/16