DESCRIPTION

One hundred years ago, there was a young boy who was seeking a unique rose for his behaved girl. That was freezing winter night, all roes had died. After a long time searching in the withered rose bushed fruitlessly, the young boy was almost desperate. Touched by his true love, a nightingale, who understood his wish, sung all night under the cold moonlight. Just before dawn, a rose stained with blood of the nightingale, bloomed, bright and fragrant.

The nightingale, created by Oscar Wilde, built a red rose for true love out of her song under moonlight. To Wilde, the unique rose stained with blood of the nightingale is the symbol of love and true art. To us UCAS-China team, the touching story should be passed down to our generation and explained in a more scientific and interesting way with the tools of synthetic biology. Furthermore, as Wilde conveyed in the story, the barrier and combination of art and science still remain worth discussing, so we also explore in depth the relationship of art and science in the Human Practices section.

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In our project which combining the four elements-music (the song of the nightingale), light (the moonlight), color (the stained rose) and odor (the rose fragrance), everyone is able to create his/her own with unique soul, together forming our rose forest in the junction of art and science!

DESIGN

In our work, the E. coli need light and sound as inputs to produce color and odor as outputs. The process is mainly divided into three parts: sound to light, light to color, and light to odor. The light-color and light-odor conversions are achieved with the RGB vision system which is based on the phage RNAP system as a resource allocator. As for the sound-light conversion, we develop a software that allows users to upload their own music to generate their unique dynamic pictures, with which people can color and ensoul their own roses.

The light control system mainly consists of 3 subsystems, a “sensor array”, an “output array” and a “signal transit”.

Firstly, the “sensor array” combines 3 sensors, Cph8* (asterisk), YF1 and CcaSR, which could be activated predominantly by red, blue and green light. These optogenetic tools enables our E. coli to response to light of different wavelengths respectively.

Why did we focus on diagnostics?

Very early on, we each came up with an idea for our iGEM project and presented it to the group. You can see some of these on our Initial Ideas page.

We carried out a public survey in the UK, where more than half of the 200 surveyed wanted a synthetic biology solution for disease diagnosis. You can read more about our surveys on our Silver Human Practices page.

We identified a gap in the field of rapid, point-of-care diagnostics which arises when antibody-based technologies cannot be used, for example diagnosis of diseases in infants or immunocompromised patients. As a result, we decided to use the flexibility and versatility of synthetic biology to design a platform technology which addresses these issues.

What is Chagas disease?

Our cell-free diagnosis kit is designed to diagnose Chagas disease in its acute phase using a simple blood test. Chagas disease is a neglected tropical disease endemic to Latin America that impacts 6-7 million people, of whom 95% lack sufficient diagnosis or treatment. We decided to focus our efforts on designing a diagnostic for congenital Chagas disease, since current point-of-care diagnostics cannot be used to detect Chagas disease in infants. Current treatments using benznidazole and nifurtimox are almost 100% effective if given shortly after the onset of the acute phase. However, lack of diagnosis leads to the onset of the chronic phase, which causes irreversible pathological consequences to the heart, digestive system, and nervous system. We hope to make a positive contribution towards this cause with our project.

You can read more about this on our Chagas disease page.

What is our solution?

We have designed two systems - one DNA based and one protein-based - to detect a protease, cruzipain. Cruzipain is produced and secreted by T. cruzi in the blood and has a specific cleavage sequence, which is ideal for the input. Our systems have bivalirudin as the output for both methods. Bivalirudin is a small peptide that acts as an anticoagulant. Therefore if bivalrirudin were produced in response to the presence of cruzipain, the blood would be inhibited from clotting. These systems are designed to be cell-free and freeze-dried to ensure safety and ease of transport, before being added to a sample of blood.

For our DNA-based system, we have designed a TetR molecule with a cleavage site for TEV protease. Our TetR will start bound to its DNA operator, repressing the production of an output protein. When it is cleaved by TEV, repression is relieved, and the reporter produced.

For our protein-based system, we have designed an amplificatory protein circuit encased in outer membrane vesicles (OMVs). Both our input (cruzipain) and our intermediate output (TEV protease) are proteases. The amplification components of our system is a split TEV protease, the two halves of which are made accessible to dimerise in the presence of cruzipain. Upon dimerisation, the protease is activated and can go on to activate more of itself in an amplificatory positive feedback loop. Active TEV protease can then cleave and release bivalirudin, which acts as the reporter of our system by inhibiting blood clotting.