Optimal Valve Diaphragm and Membrane Design for Use in Medical Catheters

Project number: 
Xeridiem Medical Devices
Academic year: 
Medical catheters are tubes inserted in body cavities, vessels and ducts to drain body fluids. The diaphragm membrane is a critical component of the catheter. It bursts at a certain pressure when a blockage occurs to allow fluids to flow through the opening created. One such use for this membrane design would be in a brain shunt to drain cerebrospinal fluid. Because of the body’s sensitivity to pressure, especially in the brain, the membrane must burst at a specific pressure to ensure no damage is done to the brain. These ultrathin membranes are difficult to produce.

This team developed a method to achieve the same burst pressure in the membrane while ensuring a consistent manufacturing process. The approach focused on creating a diaphragm membrane with an intentional slit geometry to act as a weak point and burst at a given pressure, providing an alternative path for fluid drainage. The students analyzed several slit geometries and corresponding manufacturing capabilities.

The slits in the membrane were produced using a laser ablation device. The membrane was made from biocompatible liquid silicone rubber to minimize adverse affects on surrounding tissue. The team pressure-tested its design, and, with a durometer, measured the hardness of the silicone. To ensure the system was reproducible, the team analyzed capability and performance standards using the PPK process.

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