Description
Colon Cancer
Colorectal cancer is the third common cancer and accounts for 9.7% of all cancers excluding non-melanoma skin cancer. More than half of the cases occur in well-developed regions of the world due to higher elder population, unhealthy modern dietary habits as well as continuous increase in risk factors.
In recent years, the incidence and mortality of colon cancer in China has also been on sharp increase. In some well-developed cities such as shanghai, the incidence of colon cancer has risen to the second place among all the other cancer, and even in rural areas the occurence has also rises up to the fifth place.
To see more details about colorectal cancer, go to our background page.
Why Do We Aim On Early Screening Of Colon Cancer?
Early screening is of great significance in inhibiting the progress of colorectal cancer. The earlier the disease is detected the more rapid proper treatment is performed. For the past few years, early screening of colorectal cancer has been promoted and carried out in many cities. However, due to the large imbalance in the development level of medical care across mainland China while the existing screening methods such as colonoscopy are either expensive or painful, early screening for colon cancer remains confined.
Meanwhile, synthetic biology has shown great potential as well as brand new perspectives in diagnosis and therapeutic fields for numerous harsh disease.As a result we wonder if it is possible to develop a cheaper, more convenient screening method using synthetic biology. Against all odds, we proudly present our design, ECHO.
What is Echo?
ECHO, E.coli for colon health observation, is the name of our engineered bacteria. It also highlights the most important part of our project, imaging cancerous tissues with ultrasound instead now widely-used invasive colonoscopy.
How Does ECHO Work?
ECHO consists of four parts, localization, imaging, medicine synthesis and release.
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Localization
On the surface of colon cancer cells, there are a lot of T antigens, a glycoprotein specifically presented on colon cancer cells. We equipped ECHO with a kind of oligo peptide, which can bind to the T antigen. Thus, the device can adhere to cancerous tissues.
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Imaging
Traditional diagnosis method use colonoscopy to image the cancer cells while in our project we use the gas vesicle proteins called ARG, short for acoustic reporter genes. When E.coli is transformed with this gene, it can express gas vesicles, which comprise all-protein shells with sizes of approximately 200 nm . Then we can use ultrasound to test these tiny bubbles, that is at the same time, to make the tumor visualized.
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Medicine Synthesis and Release
Besides the diagnosis section, ECHO also has part of treatment efficacy. Under the high level of nitric oxide near the cancerous tissues, the device will produce azurin, a chemical that can kill cancer cells. When the patient takes arabinose orally, a suicide circuit will be kicked over. As a result, all ECHO will die and the medicine it produces will be release to function. The suicide circuit also makes sure biosafety.
