Team:Oxford

See. cruzi

Developing a cell-free detection system for Chagas disease in the acute phase by detecting biomarkers in the blood

The aim of our iGEM project is to design a cell-free diagnosis kit to detect the presence of biomarkers specific to the Trypanosoma cruzi, the protozoan parasite responsible for Chagas disease, a neglected tropical disease impacting 6-7 million people primarily in Latin America.

Currently, the acute (early) phase of Chagas disease is difficult to diagnose, due to it being asymptomatic and methods using DNA amplification or immunoassays being both expensive and inaccessible to the majority of those affected by Chagas disease. Current treatments using benznidazole and nifurtimox are almost 100% effective if given shortly after the onset of the acute phase. However, lack of diagnosis in the acute phase leads to the onset of the chronic phase, which causes irreversible pathological consequences to the heart, digestive system, and nervous system.

The final diagnostic kit would allow Chagas disease to be diagnosed in the acute phase by preventing the clotting of a blood sample, by releasing hirudin (a peptide from leeches) upon cleavage by the protease cruzipain (a cysteine protease specific to T. cruzi). Our system would ultimately be completely cell-free, with the components freeze-dried and competent after rehydration, allowing it to be used in the field without the need for expensive equipment or highly trained professionals - all it will require is a blood sample. We imagine that this system would be adaptable for other parasites and pathogens which have similar difficulties in detection, both in the input for the system and the options for output.

We are developing two methods to detect the presence of cruzipain, both being modelled in E. coli. The first is DNA based, and involves the cleavage of a repressor protein to lead to expression of hirudin (modelled using fluorescent proteins and using TEV instead of cruzipain). The second involves tagging hirudin (again modelled with a fluorophore) to outer membrane vesicles, where the peptide could be cleaved and released from OmpA by cruzipain (modelled with TEV). Our systems would ultimately be completely cell-free, with the components freeze-dried and competent after rehydration.

Chagas disease claims over 12000 lives per year. We believe that the death toll could be significantly reduced by a synthetic biology solution, which is cost effective, accessible, and accurate in the swift diagnosis of Chagas disease; a solution that our project aims to provide.

If you want to collaborate with us, please send us an email:oxfordigem@bioch.ox.ac.uk

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