Description
Abstract
The global situation of diabetes is becoming increasingly severe, with type 2 diabetes (T2DM) accounting for over 90% of all cases. Long-term hyperglycemia can lead to serious complications in multiple organs including the eyes, kidneys, nerves, heart, and brain. Current antidiabetic drugs on the market mainly consist of oral and injectable forms, both requiring frequent administration, which not only causes inconvenience but also imposes significant psychological, physical, and economic burdens on patients.
To address this challenge, we propose an innovative strategy: engineering Escherichia coli to continuously produce glucagon-like peptide-1 (GLP-1), encapsulating the bacteria in sodium alginate-based material, and developing it into an oral formulation named "VitaPop Jelly". The engineered bacteria can stably and persistently secrete GLP-1 in the intestines, enabling a more natural and long-term regulation of blood glucose. For biosafety considerations, a temperature-sensitive promoter is used to control the expression of the key gene CysE, effectively preventing the risk of transgenic leakage and ensuring treatment safety.
We hope this approach will provide a safer and more convenient biological treatment option for diabetic patients, ultimately improving therapeutic outcomes and quality of life.
Inspiration
The inspiration for our project came from the experience of one team member's grandmother, who has been living with diabetes for many years. In an effort to stabilize her blood sugar levels, her family took her to numerous hospitals, where doctors consistently emphasized that "diet control is essential, and high-sugar foods must be completely avoided." As a result, even a comforting bowl of warm rice porridge in the morning became a "forbidden" pleasure she had to resist.
Last summer, the team member accidentally discovered her little secret: every morning when the family was busy, she would take her glucose-lowering medication from the pillbox next to the glass jar in the living room and wash it down with two slightly sweet multivitamins. The bitter pills were always hard for her to swallow, and the sweetness of the vitamins became her own small way to cope.
Watching his grandmother sitting on the balcony, gazing wistfully at the aroma of pastries from the neighbor's home, he suddenly realized: she had never resisted treatment. She diligently followed the doctor's advice and monitored her blood sugar—but no one had ever shown her how to retain small joys in life while strictly managing her condition. It was this struggle that strengthened our determination to carry out this project: to help patients like her find a balance between disease management and quality of life, so they no longer have to choose between "health" and "happiness."
Issues/Background
According to data from the International Diabetes Federation (IDF), approximately 589 million adults worldwide are currently living with diabetes, of which over 90% of cases are type 2 diabetes (T2DM). Forty percent of affected individuals reside in low- and middle-income countries, and notably, up to 40% of people with diabetes remain undiagnosed. It is projected that by 2050, the total number of diabetes cases worldwide will rise to 853 million, representing a 45% increase compared to current figures. In terms of healthcare economic burden, global diabetes-related medical expenditure in 2024 is estimated to reach approximately US$1 trillion, accounting for 11.9% of total global health spending. Beyond its substantial health impact, diabetes is responsible for about 3.4 million deaths annually and affects approximately one in five live-born infants—whose mothers experienced hyperglycemia during pregnancy[1].

Figure 1. Number of people with diabetes worldwide and per IDF Region, in 2024-2050 (20-79 years)
Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder arising from the interaction between polygenic susceptibility and environmental influences. Its central pathophysiological characteristic is progressive pancreatic β-cell dysfunction, leading to relative or absolute insulin deficiency, frequently compounded by insulin resistance in peripheral tissues—especially the liver, skeletal muscle, and adipose tissue[3]. Chronic hyperglycemia exerts extensive detrimental effects on the vascular system, triggering both microvascular and macrovascular complications. Microvascular damage predominantly involves the retina, kidneys, and peripheral nerves, presenting as diabetic retinopathy, nephropathy, and neuropathy—the last being a major factor in diabetic foot pathogenesis. Macrovascular complications markedly elevate the risk of ischemic heart disease, stroke, and peripheral arterial disease. The development and advancement of these complications significantly increase morbidity and mortality, potentially culminating in blindness, end-stage renal disease, limb amputation, or multi-organ failure[4,5].

Figure 2. Schematic overview of panvasculopathy in diabetes mellitus[4]
Although there are currently various oral antidiabetic drugs (OADs) used in clinical practice, such as metformin, dipeptidyl peptidase-4 (DPP-4) inhibitors, and α-glucosidase inhibitors, these medications can help control blood glucose levels and delay disease progression, but their efficacy is often limited by adverse effects. Gastrointestinal discomfort, including nausea, vomiting, and diarrhea, are common adverse reactions[5].
Given these limitations, there remains a pressing need to further elucidate the pathogenesis of type 2 diabetes mellitus (T2DM) and to develop new glucose-lowering agents that act on novel targets, exhibit improved efficacy, and offer enhanced safety profiles. Such advances are essential for achieving optimized glycemic control and improving long-term clinical outcomes in T2DM patients.
Current Solutions & Problems
We learned about some drugs currently available on the market for treating diabetes and found that they are mainly divided into two categories: oral hypoglycemic agents and injectable medications. Both types require frequent administration or injection, which not only places a significant psychological and physical burden on patients but also increases their financial strain. As a result, we began to explore whether it is possible to develop new treatments that could reduce the frequency of dosing while still maintaining therapeutic efficacy.
Table 1. Mechanisms and Side Effects of Common Oral Antidiabetic Drugs[5]
Drug Class | Representative Drugs | Mechanism / Target | Common Side Effects |
---|---|---|---|
Biguanides | Metformin | Reduces hepatic glucose output, Increases peripheral insulin sensitivity | Gastrointestinal disturbances (nausea, vomiting, diarrhea); rare but severe: lactic acidosis |
DPP-4 Inhibitors / GLP-1 Analogs | Liraglutide, Sitagliptin, etc. | Mimic GLP-1 or inhibit DPP-4 degradation of GLP-1, enhancing insulin secretion and suppressing glucagon | Nausea, vomiting, diarrhea; possible risk of pancreatitis in some patients |
Sulfonylureas | Glibenclamide, Glimepiride, etc. | Close pancreatic β-cell K-ATP channels to stimulate insulin secretion | Hypoglycemia, weight gain, gastrointestinal discomfort |
Thiazolidinediones (TZDs) | Pioglitazone, Rosiglitazone | Activate PPARγ to improve insulin sensitivity | Edema, weight gain, increased risk of heart failure |
α-Glucosidase Inhibitors | Acarbose, Miglitol | Inhibit intestinal α-glucosidase, slowing carbohydrate digestion | Flatulence, diarrhea, abdominal discomfort |
Our Solution
Given the range of side effects associated with current hypoglycaemic medications, we have resolved to develop a biological therapeutic approach for blood glucose reduction—specifically, probiotic-based hypoglycaemia management.
GLP-1 is a crucial incretin hormone secreted by L cells in the distal small intestine, participating in postprandial glucose homeostasis regulation through multiple pathways. Its primary mechanisms include: promoting insulin secretion in response to glucose loading, inhibiting glucagon secretion, delaying gastric emptying, and enhancing satiety (Figure 3). Concurrently, extensive rodent studies indicate that GLP-1 also promotes proliferation and differentiation of pancreatic β-cells while inhibiting their apoptosis, thereby delaying β-cell functional decline[6].

Figure 3. The Mechanism of GLP-1 in the Human Body[7]
Compared to conventional hypoglycemic agents, GLP-1 exhibits a safer, glucose concentration-dependent mode of action[8]. However, its clinical translation is severely limited by an extremely short in vivo half-life (approximately 1–2 minutes), due to rapid degradation by dipeptidyl peptidase-4 (DPP-4) and efficient renal clearance[9]. To overcome these limitations, we propose employing genetically engineered probiotics for continuous expression and secretion of GLP-1 within the intestinal tract. This approach aims to achieve sustained and stable glycemic control, offering a novel, cost-effective, and well-tolerated therapeutic alternative for type 2 diabetes mellitus (T2DM).
For our project, we used E. coli BL21(DE3)—a strain commonly employed for recombinant protein expression—as our chassis organism. Initially, we constructed the GCG gene based on literature research. However, it was found that the expressed product was the GCG precursor protein, which requires proteolytic cleavage by specific intestinal cells in humans to be converted into biologically active GLP-1—a processing capability lacking in E. coli. Therefore, through further literature review and consultation with experts, we identified the correct active GLP-1 peptide sequence and successfully engineered a bacterial strain expressing this peptide.
Due to the short length of the GLP-1 peptide, its brief in vivo half-life, and susceptibility to degradation, direct detection proved challenging. To improve detection sensitivity, we employed a fusion expression strategy with green fluorescent protein (GFP) and confirmed the successful expression of the GLP-1–GFP fusion protein.
To further enhance expression efficiency, we performed codon optimization on the GLP-1(WT)–GFP sequence, which significantly increased the expression level of GLP-1.

Figure 4. Genetic circuit diagram of GLP-1-GFP
To prevent the transgenic strain from entering the natural environment due to the excretion of the probiotic Escherichia coli that has been colonized in the intestine, we designed a survival switch. Bacteria containing plasmids usually require the addition of antibiotics in the culture medium to ensure that the plasmids do not lose during passage. However, in real usage scenarios, if patients take probiotics while also taking antibiotics, it is inevitable to disrupt the balance of the intestinal flora, leading to the abuse of antibiotics and the emergence of super bacteria.
To solve these two problems simultaneously, we utilized the characteristics of nutritional-deficient Escherichia coli that cannot survive in natural conditions. We expressed the survival-essential genes on the plasmid and used a temperature-sensitive promoter to control the expression of the survival-essential genes. This will achieve temperature-controlled bacterial suicide while also enabling stable plasmid maintenance in E. coli without the need for externally added antibiotics.

Figure 5. Genetic circuit diagram of the Kill switch
Given that our hypoglycemic probiotics are designed for oral administration, identifying a practical and well-accepted delivery vehicle for engineered bacteria was crucial. Prior to initiating experiments, our team brainstormed various potential product formats, including capsules, yogurt, oral liquid, jelly, and popping boba, while also distributing a questionnaire to gather public preferences.
Initially, considering that probiotics generally require low-temperature storage, we selected yogurt as the carrier and even incorporated this concept into the design of our team logo, uniforms, and flags. However, during a follow-up interview with Dr. Liu, an orthopedic surgeon, we learned that E. coli may ferment in dairy-based liquids and produce undesirable odors. This insight led us to abandon the yogurt option and reevaluate other product forms.
Additionally, we consulted with Manager Liu, an expert from a GMP-compliant freeze-drying workshop. We were informed that although capsules offer good stability and convenience, the production process requires expensive equipment and entails high costs, making them unsuitable for our project.
Integrating these expert opinions with the questionnaire results, we held a second round of discussions to refine the selection of the most suitable product form. Ultimately, we decided on a jelly-encapsulated "popping boba" as the delivery format and updated our team logo accordingly.
Table 2. Questionnaire survey
Question 15: If we want to use a genetically modified, safe type of E. coli that can produce substances for lowering blood sugar to have it administered to you or your family members, which method of administration would you prefer: [Multiple Choice]
Options | Subtotal | Ratio |
---|---|---|
Oral liquid | 274 | 46.44% |
Capsule-type drugs | 301 | 51.02% |
Yogurt | 201 | 34.07% |
Ice cream | 114 | 19.32% |
Gelatin-based or jelly-like products (such as milk tea with burst beads) | 154 | 26.1% |
Other | 6 | 1.02% |
I am unwilling to accept the related products | 35 | 5.93% |
The number of valid fillings for this question: 590 |

Figure 6. Results of the questionnaire
Future
In future research, we will continue to optimize the project system and strive to achieve more comprehensive functional coverage. To this end, we plan to carry out the following practical work:
Wet Lab
- In the constructed GLP-1-producing BL21 engineered strain, a glucose-sensing promoter will be integrated to enable GLP-1 expression only when the intestinal environment is under hyperglycemic conditions. This strategy aims to precisely mimic the physiological "on-demand secretion" pattern of insulin. To enhance the efficacy of GLP-1, the signal peptide and secretion system will be optimized to improve its secretion efficiency into the intestinal lumen. Additionally, stability-enhancing mutations—informed by known GLP-1 analogs—will be introduced to confer resistance to degradation by dipeptidyl peptidase-4 (DPP-4), thereby extending the in vivo half-life of GLP-1 and improving its bioactivity under physiological conditions.
- The current GLP-1-producing Escherichia coli BL21 engineered strain will be replaced with the edible probiotic strain Escherichia coli Nissle 1917 (EcN 1917) to construct a GLP-1-producing EcN 1917 engineered strain. This transition lays a safety foundation for the subsequent development of edible oral formulations.
- Following the successful construction of the GLP-1-producing EcN 1917 engineered strain, the next step involves utilizing coaxial extrusion technology for encapsulation to produce the oral formulation "VitaPop Jelly". The preliminary steps are as follows: sodium alginate and a 4% calcium chloride solution will be prepared and loaded into two syringes connected to a coaxial needle. Simultaneous extrusion will form core-shell droplets, which will be dropped into a calcium chloride solution for shell solidification. The resulting beads will then be collected and washed. This method is expected to effectively protect the bioactivity of GLP-1 and enable its oral delivery.
HP
We will maintain ongoing communication with stakeholders to gain a deeper understanding of regulations and market access related to food-use strains and genetically modified organisms, actively explore mechanisms for maintaining gut microbiota health, and thoroughly understand the psychology and expectations of different consumers. Building on this, we will implement a rigorous and scientific safety assessment process to steadily advance product development and commercialization.
Entrepreneurship
We will actively pursue the registration of "Vitapop jelly" as a Formula Food for Special Medical Purposes, strengthening efficacy verification and compliance development. By optimizing the fermentation process for GLP-1 engineered bacteria and microencapsulation technology, improving the supply chain system, and securing financing to accelerate industrialization, we aim to launch co-branded anti-sugar beverages in collaboration with popular tea drink brands in the future. Additionally, we will expand into online e-commerce and offline pharmacy channels, while building a technological barrier through global invention patents. Our commitment is to provide a safe, delicious, and effective daily blood glucose management solution for sugar-conscious consumers worldwide.
Education
We will maintain continuous interaction with adolescents by developing more effective and engaging educational interactive installations to simplify the understanding of synthetic biology and extend the reach of its achievements to a broader audience. In addition, we will visit schools in different regions to promote our project and the vitapop jelly product, raising awareness among young students about diabetes prevention and contributing, in our own way, to curbing the trend of diabetes among younger populations.
References
- International Diabetes Federation. (2025). IDF Diabetes Atlas 11th edition 2025. https://idf.org/about-diabetes/diabetes-facts-figures/
- Li Y, Liu Y, Liu S, Gao M, Wang W, Chen K, Huang L, Liu Y. Diabetic vascular diseases: molecular mechanisms and therapeutic strategies. Signal Transduct Target Ther. 2023 Apr 10;8(1):152.
- Zhou, D., Li, S., Hu, G., Wang, Y., Qi, Z., & Xu, X., et al. (2025). Hypoglycemic effect of c. butyricum-pmtl007-glp-1 engineered probiotics on type 2 diabetes mellitus. Gut Microbes, 17(1).
- Committee, A. D. A. P. P. (2025). Introduction and methodology: standards of care in diabetes—2025. Diabetes Care, 48(Sup1).
- Nathan, D., Buse, J. M., Ferrannini, E., Holman, R., Sherwin, R., & Zinman, B. (2008). Medical management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy. Diabetes Care.
- T.D. Müller, Finan, B., Bloom, S. R., D'Alessio, D., Drucker, D. J., & Flatt, P. R., et al. (2019). Glucagon-like peptide 1 (glp-1). Molecular Metabolism, 30(C), 72-130.
- Wang, J. Y., Wang, Q. W., Yang, X. Y., Yang, W., Li, D. R., & Jin, J. Y., et al. (2023). Glp-1 receptor agonists for the treatment of obesity: role as a promising approach. Frontiers in Endocrinology, 14(000), 11.
- Nauck, M. A., Kleine, N., Orskov, C., Holst, J. J., & Creutzfeldt, W. (1993). Normalization of fasting hyperglycaemia by exogenous glucagon-like peptide 1 (7-36 amide) in type 2 (non-insulin-dependent) diabetic patients. Diabetologia, 36(8), 741-744.
- Holst, J. J. (2007). The physiology of glucagon-like peptide 1. Physiological Reviews, 87(4), 1409-1439.
- Stirling F, Bitzan L, O'Keefe S, Redfield E, Oliver JWK, Way J, Silver PA. Rational Design of Evolutionarily Stable Microbial Kill Switches. Mol Cell. 2017 Nov 16;68(4):686-697.e3.
- Hayashi N, Lai Y, Fuerte-Stone J, Mimee M, Lu TK. Cas9-assisted biological containment of a genetically engineered human commensal bacterium and genetic elements. Nat Commun. 2024 Mar 7;15(1):2096.
Contributions
Overview
Our project delivers a comprehensive toolkit for synthetic biology, featuring four key contributions. We provide a high-yield GLP-1 expression system in E. coli, solving a common protein production bottleneck. To ensure safety, we engineered a robust, antibiotic-free "Kill switch" that prevents environmental leakage. For future therapeutics, we designed "VitaPop," a novel oral delivery platform that protects engineered bacteria and integrates treatment into a palatable format. Finally, we created the "LARS" educational framework and tools to empower future teams in public outreach. Together, these offerings provide foundational resources for safer, more effective, and socially engaged synthetic biology applications.
Functional and well-characterized GLP-1 expression components
We have designed, constructed, and characterized codon-optimized GLP-1(OP) and GLP-1(OP)-GFP fusion proteins for high-efficiency expression in E. coli. All detailed sequence information, design schematics, sources, and functional descriptions of these components have been uploaded to the iGEM Parts Registry. Experimental results confirm that the codon optimization strategy significantly enhances GLP-1 expression levels in E. coli, laying a critical foundation for the practical application of this protein engineering effort.
What we provide:
We have developed a thoroughly validated GLP-1-GFP expression system. Based on a codon-optimized GLP-1 gene sequence, this system enables efficient and stable expression of GLP-1 and its GFP fusion protein in E. coli. We provide complete plasmid construction maps, optimized expression condition data, and detailed protocols for protein expression and detection, demonstrating that the system achieves high protein yield in E. coli.
Why it's a contribution:
1. Addressing Expression Bottlenecks:
GLP-1 often suffers from low expression levels and poor stability in E. coli. Our experimentally validated GLP-1 expression system enables high-efficiency production and serves as a modular foundation for future teams to adopt directly. This system provides a reliable "expression chassis" for developing GLP-1-based diabetes therapy research.
2. Providing an Expandable Modular Framework:
Future iGEM teams can build upon this validated GLP-1-GFP expression framework by integrating functional modules such as protein stability enhancement tags, secretion signal peptides, or co-expressed molecular chaperones. This allows systematic improvement of GLP-1 expression levels, stability, and bioactivity, offering a robust platform to address the complex demands of type II diabetes treatment and expand applications in synthetic biology.
A Robust, Antibiotic-Free Biosafety "Kill Switch"
In synthetic biology applications, especially in fields like live therapeutics and environmental applications, biosafety is a critical and core issue. Our project provides a fully validated, integrated solution to address two common challenges: the environmental leakage risk of genetically engineered strains and the reliance on antibiotic selection.
What we provide:
We have designed, built, and validated a dual-action biosafety module. This module is based on the knockout of a key metabolic gene (CysE), rendering the E. coli chassis a cysteine auxotroph. We placed the CysE gene under the control of a temperature-sensitive promoter (I38) and integrated it onto a plasmid. We provide the complete strain, plasmid construction protocols, and detailed characterization data, demonstrating that the system grows normally at 37°C (simulating the gut environment) but undergoes apoptosis at temperatures below 33°C (simulating the natural environment).
Why it's a contribution:
This work provides the iGEM community with a powerful safety tool, significantly lowering the barrier for future teams to design for real-world applications.
1. Addresses a Core Safety Concern:
Nearly all projects using live engineered microbes must consider the risk of genetic leakage. The "Kill switch" we provide is a ready-to-use solution that causes the engineered bacteria to die automatically upon leaving the host, effectively preventing horizontal gene transfer and potential ecological impacts. This offers a reliable "safety lock" for future teams aiming to develop probiotics, in-vivo biosensors, or environmental remediation applications.
2. Eliminates Antibiotic Dependence:
Using antibiotics to maintain plasmid stability is not feasible in practical applications. Our system cleverly utilizes a plasmid selection mechanism based on auxotrophy: the strain's survival is dependent on the CysE gene located on the plasmid. This ensures high plasmid stability across generations without any need for antibiotic selection. This not only avoids the risks of antibiotic misuse but also provides a valuable solution for teams planning to apply their projects in antibiotic-free environments, such as fermentation or agriculture.
VitaPop: Reinventing Oral Delivery with the "Microbe-Jelly"
In the field of live biotherapeutics, oral delivery is a highly attractive administrative route. However, it faces two major challenges: degradation by strong gastric acid and low colonization efficiency of live bacteria in the intestine, which severely limits its efficacy and practical application. Our project aims to explore the feasibility of a novel oral delivery approach through the integration of synthetic biology and food engineering.
What we provide:
We have designed and preliminarily constructed a conceptual prototype of a multi-layer delivery system named "VitaPop". The core of this system is an "ECN-in-bead-in-jelly" (engineered bacteria - bursting bead - jelly) three-level structure:
- Inner Protection Layer: Engineered bacteria are encapsulated in sodium alginate-chitosan microcapsules ("bursting beads"), designed to provide gastric acid protection and enable targeted intestinal delivery.
- Outer Carrier Matrix: These bacteria-loaded microcapsules are embedded within a palatable jelly matrix. Utilizing jelly—a widely accepted food format—as the oral delivery vehicle lays the foundation for seamlessly integrating the treatment process into patients' daily lives.
Why it's a conceptual contribution:
Although full biological validation requires future experimental confirmation, this work provides the iGEM community with a novel and explorative delivery design framework.
1. Providing an Innovative Design Strategy for Oral Delivery Challenges:
We clearly identify the bottlenecks of oral delivery and propose an elegantly structured solution. This preliminary scheme offers a clear, testable, and optimizable technical pathway for future teams addressing similar problems.
2. Pioneering the Integration of Therapy and Daily Experience:
The core contribution of this concept lies in its design philosophy—merging synthetic biology applications with a highly acceptable food format. This provides a novel and promising direction for future development of biomedical applications that prioritize patient compliance and quality of life.

The multi-layer delivery system of "VitaPop"
Educational Framework: Transforming Public Outreach through "LARS (Learn–Adapt–Realize–Summarize)"
In the field of public health and science education, one of the key challenges lies in transforming abstract knowledge into impactful, audience-centered interventions. Many educational initiatives struggle due to the absence of a clear methodological pathway and limited opportunities for reflective improvement. To address this, we developed the LARS principle, a structured and iterative educational framework that emphasizes preparation, adaptation, practical implementation, and continuous refinement.
What we provide:
We have established and applied the LARS principle, which guides teams through a cyclical process of designing and executing effective educational activities.
- L: Learn — Study existing award-winning strategies and scholarly approaches; analyze current educational methods, tools, models, and processes; and evaluate their effectiveness.
- A: Adapt — Select educational approaches suitable for specific audiences (e.g., adolescents) and refine them to create a tailored program.
- R: Realize — Boldly implement the designed program in real-world educational settings.
- S: Summarize — Conduct timely reviews and evaluations after each activity to identify strengths and weaknesses, ensuring continuous optimization and iteration.
This principle provides teams with a replicable cycle of preparation, action, and reflection, offering a practical pathway for long-term educational innovation.
Why it's a conceptual contribution:
1. Offering a Reusable Design Principle
LARS provides a structured, generalizable framework that can be applied across various scientific and health education contexts. By combining preparatory research with adaptive implementation, it lowers the barrier for future teams to design evidence-based and effective interventions.
2. Enabling Iterative and Sustainable Improvement
By embedding review and iteration as core steps, LARS ensures that educational strategies remain relevant, effective, and adaptable. This cyclical improvement mechanism enables iGEM teams to evolve their outreach efforts over time, making education more sustainable and impactful.
3. Promoting Deliberation before Execution
LARS highlights the importance of critical thinking and careful preparation prior to action. By thoroughly analyzing existing methods before implementation, teams can anticipate challenges, reduce inefficiencies, and deliver more targeted, high-quality educational activities.