Low-cost, Extrudable, Biocompatible Catheter Body for the Physical-Plasma Cardiovascular Catheter

Overview

In a recent medical advancement, plasma has been used as an effective sterilizer against bacterial pathogens. Our sponsor, Dr. Sean Knecht, has developed a novel-plasma generating geometry to treat cardiovascular illnesses such as endocarditis, atherosclerosis, and septicemia.

Objectives

The main objective of this project is to extrude a cardiovascular catheter body to integrate the novel plasma-generating geometry developed by our sponsor. Supporting objectives include:

– Selecting a horizontal extrusion device, within budget, capable of high-quality extrusion 


– Designing extrusion nozzles of zero, single, and dual-lumen configurations, compatible with the 
selected horizontal extrusion device, to extrude a cardiovascular catheter body, over an 
electrode wire, containing a custom cross-section 


– Selecting a material for the cardiovascular catheter body that is low-cost, biocompatible, and 
has sufficient mechanical and electrical properties

Approach

– After gathering customer needs from our sponsor, for each of the three supporting project objectives, technical specifications were established. 


– Research was conducted to guide the selection of the final horizontal extrusion device and materials for the extrusion nozzle and catheter body. 


– Concepts were generated for the nozzle exit and corresponding catheter body cross-sections. 


– Nozzle designs were modeled in SolidWorks and sent to Xact Metal to be additively manufactured. 


– A Taguchi array was created to determine the optimal settings for the horizontal extrusion system. 


– Catheter body prototypes were extruded and detached in 8–12 inch segments. 


– Testing was conducted to analyze the consistency, rigidity, and dielectric strength of the successful 
extrusions. 


Outcomes

A single-lumen catheter body was successfully extruded over a molybdenum electrode wire. In addition to the single-lumen design, nozzles to extrude a zero and dual-lumen catheter body were modeled. 


– Regarding consistency, although the outer diameter of the extruded catheter body did vary, the 
moving average remained within a 0.08 mm diameter tolerance. 


– Because the applied compressive force did not cause plastic deformation during the buckling test, 
the catheter body was deemed to have sufficient rigidity. 


– During the HIPOT test, plasma was successfully generated at the tip of the electrode with no 
indication of dielectric breakdown.