Background
The intestine, as part of the digestive system, plays a vital role in the human body. Intestinal bleeding can be caused by a variety of diseases, such as enteritis, tumors, enteric tuberculosis, perianal diseases, and is aprecursor to many diseases. Therefore, timely detection of intestinal bleeding is very important.
Colonoscopy is currently the most commonly used and effective method of examination, but some people still have difficulty with the discomfort associated with receiving a colonoscopy. At the same time, a large amount of intestinal bleeding we can directly judge by self-perception and changes in stool color, if it is a trace amount of bleeding, fecal occult blood experiment (FOBT) is often used clinically. By looking for relevant information, we understand that FOBT often requires subjects to keep their own stool specimens, which are then transport and handed over to the hospital for testing, resulting in a low actual detection rate of fecal occult blood. In addition, false positives can occur if you have eaten chlorophyll-containing foods, animal blood and iron-containing drugs in the daysleading up to the test, which can greatly affect the diagnosis. After interviewing laboratory doctors, we also learned that the reagents used in fecal occult blood tests are unstable and carcinogenic, causing some harm to the body.
At the same time, there are still some remote areas in China with relatively backward medical conditions, and people often cannot be found and treated in time when they get sick. Therefore, we are committed to designing a portable intestinal microbleeding detector, the expected results that we hope to improve the sensitivity and specificity of the detection, to a certain extent to avoid the impact of food and other factors on the test results, and to protect the environment, reduce costs and other issues to contribute, give full play to our advantages.
A new strategy provided by us -- biosensors for detecting intestinal microbleeds
Heme intracellular transport expression system
A kind of safe and harmless probiotics -- Escherichia coli Nissle 1917
Regarding the choice of chassis, we decided to use Escherichia coli Nissle 1917, which has been proven to be a probiotic that is harmless to the human body. They are naturally present in the gut and adapt to the environment. More importantly, E. coli Nissle 1917 has been used to treat several gastrointestinal diseases. Several studies have shown that E. coli Nissle 1917 can secrete vesicles to maintain the intestinal barrier and prevent intestinal infection by inducing the secretion of antibacterial peptides. Moreover, since Escherichia coli Nissle 1917 is a facultative anaerobe that can be fixed in the intestine, their presence can be detected in the excreted feces. Therefore, we decided to use Escherichia coli Nissle 1917 as the chassis. By culture of bacteria in faeces, culture and observation of the color of the bacteria, the diagnosis of chronic lower gastrointestinal bleeding can be achieved.
Bacterial greenhouse -- a simple device for bacteria isolation and culture
Because the bacteria content in the feces is not enough, it is difficult to observe the blue color. Therefore, we have designed a simple bacterial isolation and culture device that can be used in non-laboratory conditions. The device is mainly composed of two parts: the separation device and a culture device. To achieve the separation of the probiotics, we need to mix the well-tested stool samples and then pre-place them in a syringe with a filter membrane with a specific aperture. And then squeeze the probiotics into the collection device. In the collection device, we pre-load the culture medium with dry powder, and add water when using it in order to make it become a liquid culture medium. In addition, we have designed a simple and general oscillating heat preserving device that oscillates at a certain temperature. Finally, we will judge the presence of heme by observing whether there is a change in color, so as to judge whether there is intestinal bleeding. If blue is present in the culture medium, it indicates chronic lower gastrointestinal bleeding; Conversely , there was no chronic lower gastrointestinal bleeding.
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