Month: October 2020

These two weeks, the team has focused on initial design.

Our first idea for the valve is to use PyKC, a novel hydrogel. This hydrogel is insoluble in water and biological fluids. DMSO, frequently used for bladder flushing, could be used to degrade PyKC, making for a simple removal process when the device is no longer needed. As this is a novel material, more information is needed to finalize decisions going forward.

Our Second idea is to utilize a metal frame with a coating and a mesh within. The frame would be designed to have a ring of hollow tubes allowing it to expand and contract as needed. It would also be coated in a layer such as silicon dioxide to prevent cell growth.

For the catheter, we are planning to utilize a delivery mechanism similar to the procedure to implant ureteral stents. Via cytoscope, a guidewire is inserted into the urethra, through the bladder, and up the ureter. Once in position, the stent is fed along this wire with a catheter “pusher,” until the stent is in the proper position. At this point the guidewire and pusher are removed, leaving the stent behind.

Additionally, the team has set up an initial budget and gaant chart to follow. Subject to change.

Budget

Gantt Chart – This is the schedule we anticipate to follow for the remaining duration of this project.

This week, the team has focused on design standards to follow. Standards, developed by experts in their field, are rules, testing methods, definitions, recommended practices, or specifications that promote uniformity. Below are the standards that will be referenced in the design and testing of this project. Subject to change.

Standard	Name	Justification
ASTM F1635-16	Standard Test Method for in vitro Degradation Testing of Hydrolytically Degradable Polymer Resins and Fabricated forms of Surgical Implants	This standard will be referenced in the consideration of different materials that could be used as the material for the valve, if a biodegradable material is the option chosen.
UNE – EN 13868-2002	Test Methods for Kinking of SIngle Lumen Catheters and Medical Tubing	This standard will be referenced in the testing of the polymer and how the effects of different pH values change it’s properties due to degradation.
D3826-18	Standard Practice for Determining Degradation End Point in Degradable Polyethylene and Polypropylene Using a Tensile Test	This standard will be referenced in both the catheter and valve design. The standards for leakage and surface properties will be utilized, in addition to the testing parameters for leakage, pressure under standard conditions, and the determination of flow rate through the valve. Though the catheter will be a short-term implantation into the body, the valve should follow the constraints of a normal catheter for long-term placement in the body.
ISO 10555-1ASTM F2004-05	Intravascular Catheters Sterile and Single-Use Catheters	These standards will be referenced in designing the valve. The material that will be used to design the device has not been chosen but there is a possibility of using an alloy. These two standards provide procedures that determine the transformation temperatures of nickel-titanium shape memory alloys.
ASTM F2082-06	Standard Test Method for Transformation Temperature of Nickel-Titanium Alloys by Thermal Analysis
ASTM G71-81	Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes	This standard will be referenced in the valve design. Since a material has not been picked yet, it is possible that a metal or a polymer and a metal combination will be used, making this standard necessary for testing. This standard covers corrosion tests when in contact with electrolytes under low flow conditions, and will likely have to be modified to be used for the valve design.
FDA Code of Federal Regulations Part 876.513	Urological catheter and accessories	This code will be referenced with respect to the catheter, as this code discusses catheters used in the urethra. It also discusses how the catheter is classified, based on some requirements.