Session: ASME Undergraduate Student Design Expo

Paper Number: 172939

Fabrication and Characterization of Continuous Pcl Microfibers 

Flow diverters (FDs), braided metallic microwire-based highly dense meshed tubes, have become the most effective fluidic biomedical devices for endovascular treatment of aneurysms. Despite the great clinical successes, the permanent installation of metallic FDs can cause post-cure clinical complications such as late thrombosis, embolism, and limit the future electromagnetic-based diagnostics such as MRI, CT scan, etc. To mitigate these drawbacks and potential risks, there is a growing effort on the development of bioresorbable flow diverters, so that they can be absorbed after complete cure of the aneurysm and remodeling of the blood vessel network. However, the bottleneck in the development of bioresorbable FDs is the unavailability of continuous bioresorbable microfiber or microwire with appropriate mechanical properties and hemobiocompatibility. This poster presents the novel fabrication process and characterization of continuous, spoolable polycaprolactone (PCL) microfiber for developing bioresorbable, braided flow diverters. A patent-pending in-house electro-melt spinning unit was designed and developed. The unit consists of a temperature-controlled hotend nozzle, 2 stepper motors, a fan, and a spooling bobbin. Medical grade regular 3D printing PCL filament is fed into the hotend nozzle by the first stepper motor, and the microfiber is pulled from the hotend nozzle to spool on the bobbin by the second stepper motor. The diameter of the PCL microfiber was controlled by the spinning rate of the spooling bobbin and the feeding rate of the PCL filament into the hotend. Four different spinning rates – 15 rpm, 30 rpm, 60 rpm, and 120 rpm and three different feeding rates – 0.047 mm3/s, 0.071 mm3/s, and 0.095 mm3/s were used to produce 50 ft long PCL continuous microfibers. The surface quality of the fibers was visually inspected and quantified through atomic force microscopy (AFM), and the diameters of microfibers were measured using scanning electron microscopy (SEM). For 0.095 mm3/s feeding rates and the spinning rates of 15 rpm, 30 rpm, and 120 rpm, the diameters of the produced PCL microfibers were found to be 114 micrometers, 81 micrometers, 68 micrometers, and 33 micrometers, respectively. The results show that for a fixed feeding rate, the diameters of the produced fibers are inversely related to the spinning rates. The fiber diameter decreases with increasing spinning rates. Also, for 30 rpm spinning rate and the feeding rates of 0.047 mm3/s, 0.071 mm3/s, and 0.095 mm3/s, the diameters of the produced microfibers were measured to be 56 micrometers, 74 micrometers, and 81 micrometers, respectively. The results also show that for a fixed spinning rate, the fiber diameters increase with the increase in the feeding rates. The average microfiber roughness was found to be 20 nanometers, which is comparable to the typical microscopic glass slide surface roughness. The developed spinning unit is able to produce 2-micrometer-diameter to 300-micrometer-diameter continuous PCL microfibers by modulating spinning rates and feeding rates. The development spinning unit can produce other microfibers, such as PLA and PLLA microfibers. This research is a step forward in developing bioresorbable braided flow diverters for the treatment of brain aneurysms.

Presenting Author: Casey Bond University of Central Oklahoma

Presenting Author Biography: Casey is a undergraduate research assistant at the University of Central Oklahoma

Authors:

Mohammad Hossan Univ Of Central Oklahoma
Casey Bond University of Central Oklahoma
Alex Matsayko University of Central Oklahoma