ProjectsCollection

Dynamic Satiety Stimulator

Lack of persistent weight loss may limit current intragastric balloon therapy. Intragastric balloons that do not change in volume are associated with stomach accommodation, resulting in plateauing weight loss. Along with a team of PhD's and students, I have designed one of two endoscopically administered gastrointestinal devices that support dynamic satiety induction with each meal.

The device expands before meals and occupies the stomach, then shrinks to a minimal volume after the meal. The system is programmed to stimulate satiety autonomously over the course of treatment, and we conducted preliminary evaluations in vitro and in vivo in swine models. With this, we explore a minimally invasive dynamic satiety induction device to support weight loss.

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Working on the inflating gastric balloon device marked my first experience with medical device design and let me see the purpose of addressing real-world health challenges.

Throughout this project, I was introduced to the experimental design process to validate a concept and keep iterating. I improved my CAD and data analysis as we had experiments with fixtures that ran over multiple days and had to process the data to extract our insights. I also gained hands-on experience with PCB design, soldering components onto boards, and performing in vivo tests on swine, where we did both initial proof-of-concept and longer-term studies.

Overall, this project was a great introduction to the medical device field, showing me the process behind advancing healthcare technologies.

Takeaways

Design thinking
Experiment design
CAD
MATLAB
PCB design

Process

Motivation

With rising rates of obesity, there is a growing need for more effective, minimally invasive treatments. Traditional methods such as diet, exercise, bariatric surgery, and pharmacological interventions have shown limitations in either efficacy or invasiveness. One common method, static intragastric balloon therapy, initially induces feelings of fullness, but over time, patients often experience accommodation, leading to a plateau in weight loss and diminishing results.

We looked to address this by creating a dynamic gastric balloon device that could more closely mimic natural satiety processes. Unlike static balloons, our design expands before meals to stimulate satiety and deflates afterward to prevent stomach accommodation.

By designing this device, we aimed to provide a novel solution that combines the benefits of minimally invasive therapy with improved efficacy, offering a potentially improved approach to weight loss for individuals struggling with obesity.

Goals

The goal of this project was to design and develop a dynamic gastric balloon stimulator that could address the shortcomings of existing intragastric balloons. By mimicking the natural expansion and contraction of the stomach during meal times, the device could help reduce food intake and promote sustained weight loss.

Key design requirements for our project included:

Dynamic Expansion and Contraction: The balloon needed to inflate pre-prandially to fill the stomach and induce satiety, then deflate post-prandially to prevent accommodation and maintain effectiveness over time.
Minimally Invasive Delivery: The device had to be designed for endoscopic delivery, so that the procedure was safe and minimally invasive for patients.
Long-Term Gastric Residency: The balloon system needed to withstand repeated cycles of inflation and deflation over an extended period in the stomach.
Safety and Precision: The device required precise control over inflation to avoid over-expansion and ensure patient safety.
Portable and User-Friendly: The design had to include a compact, portable control system for easy management of the device.

By meeting these requirements, our goal was to create a safe, effective, and user-friendly device that could significantly improve the treatment options available for individuals with obesity.

Progress

Concept
The project began with researching existing obesity treatments, focusing on the limitations of current intragastric balloons, which led to the idea of a dynamic balloon design. Our goal was to develop a balloon that could inflate before meals to induce satiety and deflate after meals to prevent stomach accommodation and therefore increase weight loss efficacy.

Prototyping and CAD Design
Once the concept was fleshed out, we moved into the prototyping phase. Using CAD, we developed models of the balloon inflation mechanism and the necessary fixtures for deployment. The balloon was designed to inflate and deflate based on a custom PCB and Teensy 3.2 board for automated control. Additionally, we needed the device to be able to be endoscopically deployed and safely and effectively reside in the stomach for extended periods. Throughout this phase, prototypes were developed with each iteration refining the materials and structural components to balance flexibility, durability, and precision.

In Vitro Testing
Through prototyping, we began in vitro testing to validate the functionality and robustness of the device and materials. This testing phase focused on the inflation and deflation cycles of the balloon within a simulated neutral and acidic stomach environment. The system was connected to a portable control pack, and the balloon was inflated and deflated according to pre-set schedules to mimic feeding times. Data was collected through sensors to ensure precise pressure control and to monitor the durability of the balloon during repeated cycles of inflation.

PCB Development and Circuit Design
Simultaneously, we created the electronic components of the device. The Teensy 3.2 board was programmed to control the inflation and deflation cycles through a custom PCB, which included an airflow control system, pressure sensors, and safety features. At this stage, I learned about PCB design and how to put together a PCB board to automate the air pressure control and to monitoe the balloon’s volume in real-time.

Proof of Concept In Vivo Testing
After successful in vitro testing and results, the next step was to evaluate the device’s performance in a live animal model. We conducted initial in vivo tests using swine models, where the balloon was placed endoscopically into the stomach and inflated. The results from these tests were crucial in confirming the ability of the device to inflate and deflate safely and effectively in a real gastric environment. We monitored balloon inflation dynamics and overall system performance, which informed us that our device was mechanically and materially effective.

Data collected from sensors embedded in the balloon helped verify that the inflation cycles reduced food intake significantly—over 60% compared to control groups. This validated the efficacy of our dynamic approach in inducing satiety, as intended.

Long-Term In Vivo Testing
We then conducted a longer-term in vivo study to validate the balloon stimulator’s performance over time on feeding habits. The balloon was deployed in swine models over several days, with the system operating multiple cycles of inflation and deflation daily according to their feeding schedule. These longer-term tests focused on evaluating the durability of the device, the balloon’s ability to maintain its integrity over time, and the impact of the device on feeding behavior. We also looked for signs of adverse effects such as tissue irritation or improper function. The results showed consistent reductions in food intake – over 60% reduction compared to control groups – and the balloon demonstrated resilience throughout the study period, with no significant signs of degradation or malfunction.

Conclusion