“If you are feeling really sick, you do everything to feel better” - Interviewed patient

Here you will find the total description of our project, beginning with our team formation and motivation, continuing all the way to our final product and future research. Throughout the page, you will find links to the rest of our wiki for more detailed descriptions and information.


The two-component sensing system described in the paper above was characterized and tested versus a wide range of intestinal metabolites, receptor-ligands and tetrathionate analogues at well over physiological concentrations to test for specificity of our transmembrane receptor protein TtrS. Of these molecules, only tetrathionate yielded a response [14]. More information about the specificity of our system can be read in our Integrated Human Practices segment The Science and on our Proof of Concept page.


During discussions with experts, it was brought up that endoscopies can only be performed by gastroenterologists, a nurse cannot carry out an endoscopy. An ultrasound scan on the other hand, is easier to use. Some practice and training is required, but image-analysis can be considerably automated. In addition, it is no longer needed to follow fasting instructions or take strong laxatives, and instead, simply ingesting a pill is a considerable improvement in the ease-of-use for the patients.


Taking an endoscopy is expensive, and average costs usually fall between 700 and 800 dollars. Ultrasound procedures on the other hand, only tend to cost less than 120 dollars, with an average procedure of the intestine costing around 90 dollars. Given the low specificity of the calprotectin test, ruling out false positives can be very cost effective, especially when considering the gain in quality of life. A cost analysis was performed and included on our Implementation page.

Fast Imaging

Conducting an endoscopy takes around 30 minutes, and requires a gastroenterologist as well as two nurses to perform and prepare [15]. An ultrasound measurement can be done by a single person and takes under 30 minutes to perform, typically around 20 minutes for the abdominal area [16,17]. This effectively competes with the current method and is generally faster while requiring less staff to perform. More on this is further touched upon on our Implementation page.

Project - IBDetection

To integrate the sensing part from the two-component system with the ARG to use as output as described above, two design strategies—design A & B—were devised to achieve the functioning protein network as shown below. More on the design strategies, and why they were necessary can be read on our Proof of Concept page. The complete cascade starts with the transmembrane receptor protein TtrS that binds to the biomarker tetrathionate with high specificity. Our regulator protein TtrR is subsequently phosphorylated and forms a homodimer, which acts as a transcription factor for our ARG. This leads to transcription and translation of our gas vesicle proteins, and eventual oligomerization into gas vesicles, which can then be detected using ultrasound technology. All mechanisms are described in much greater detail on the Proof of Concept page, and supplementary part information is included on the Parts page. In addition, we also wrote an extensive model to analyse and estimate and study the behaviour of this mechanism, which can be found on our Model page.

This mechanism is envisioned to be incorporated into gut-safe bacteria, which in turn will be incorporated into a pill design that releases them alive to the intestine, where they will migrate down through the colon and act as living sensors. We discussed with many stakeholders, including doctors, patients and field-specific companies on the application of our product in industry, the delicate choice of bacteria and intricate pill design. In addition, we delegated a lot of our attention to the safety and ethics of our product, as well as GMO legislation, to gain insight on and take into account the many details on devising and developing a product that would utilise live GMOs for the purpose of healthcare & monitoring.

Over the course of the project, we have validated our individual components, and worked hard on developing a proof-of-concept to show that the mechanism functions in a range of bacteria, including our E.coli BL21 (DE3). This illustrates the huge potential of being able to implement our entire system in any desired bacterium. More on these results can be read on our Results page. This culminated in the development of a new composite part BBa_K3972004, which describes a tetrathionate sensor with transferred TtrR and pTtrB activated ARG on the same plasmid, as described on our Parts page. Parallel to our proof-of-concept, we also set out to add to the iGEM library by improving the existing part BBa_K801100. We improved this Red Fluorescent Protein (RFP) coding part by exchanging the old ribosome binding site (RBS) for a five prime untranslated region (5’UTR), which can be read about on our Part Improvement page.


In practice, we expect the potential of IBDetection to be significant in both industry to save on costs and labour, and for the patient due to the non-invasive nature, fast methodology and ease-of-use. This is because in addition to its inherent benefits, no laxatives have to be taken, and no fasting is required beforehand. This potential is further elaborated upon on our Implementation page. Results from patient consultations and questionnaires were positive, with very realistic requirements that would have to be met, such as gut microbiome safety. Results from the lab and our model also pointed to a promising future prospect, with components working as anticipated, and predictions being optimistic for effective ultrasound imaging.

Future Prospects

The future prospect will primarily consist of further establishing and characterizing our proof-of-concept, especially in different—more suitable—cell types, such as L. Plantarum WCFS1. Additional mechanisms could be introduced to ensure full control over safety, depending on future GMO-usage requirements. Naturally, patenting and particularly pill development are on the future agenda, and are described in detail on our Implementation page. In the end, we aim to provide the industry with a cost-effective and easy-to-use solution for the current lack of specificity in the home calprotectin test and offer a non-invasive fast-imaging additional intermediate procedure to rule out false positives with IBDetection.

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