My undergraduate thesis project was done in the Langer and Traverso Laboratories at the MIT Koch Institute for Integrative Cancer Research. This research was conducted under the supervision of Prof. Gio Traverso, Prof. Robert Langer, and Dr. Malvika Verma.
The goal of the project was to develop a gastric resident device capable of:
Loading and dispensing large doses (100mg per day) of solid medication (pills)
Reside in the gastrointestinal (GI) tract for at least one month
Releasing the medication in controlled, pulsatile manner
Shown below are two early, working prototypes of the device. One device is driven by hand to verify the functionality of the internal pill release mechanism. The other device is driven by a motor to demonstrate the system's ability to be actuated autonomously.
A recent prototype of PES. Shown is the housing containing the pill release mechanism and pills. Onboard electronics are not shown, but are in a separate housing added to the ends of this prototype.
The project was motivated by medication non-adherence. Patients tend to not follow instructions for medication administration exactly as directed, which can lead to decreased treatment effectiveness and increased risk of developing antibiotic resistance. The proposed strategy for overcoming this problem was the use of gastric resident devices, devices which reside in the stomach for long periods of time and perform some task in the process (in this case, drug delivery).
The developed device takes an electromechanical approach to achieving the above design requirements. My responsibilities on the project included:
Conceiving of and developing mechanisms to achieve pulsatile release of solid pills
Designing prototypes to achieve proof of concept of devised mechanisms
Refining designs for manufacturability, biocompatibility, and safety
Exploring backflow prevention strategies to protect the interior of the device
Design and implement electronic control schemes to actuate the pill release mechanism
Present and document the project for journal publication, patent application, and undergraduate thesis
Most of the design work was devoted to developing the pill release mechanism, the part of the device responsible for ejecting pills from the housing. It uses a crank-slider mechanism (similar to that used in a car engine's pistons) to achieve a pushing motion while being driven by a motor. This mechanism has many advantages:
It is compact
It simplifies control, allowing the motor to be driven with an on-off control scheme
It can be driven in one direction, further simplifying control
A schematic of the pill release mechanism showing how a motor driven in a single direction allows for a repeatable, pushing motion at the output.
Other modules which required development on this device were:
Housing design and material selection
Backflow prevention
Design of pill exit doors (to prevent unreleased pills from leaving the device)