Embedded Files
Problem Statement
Problem Statement
The ability of 3D-printed intraluminal airway stents to be properly deployed using similar deployment methods need to be assessed to ensure the stent will perform as intended.
The ability of 3D-printed intraluminal airway stents to be properly deployed using similar deployment methods need to be assessed to ensure the stent will perform as intended.
Experimental Workflow
Experimental Workflow
24 Hour Compression
24 Hour Compression
The PCL stents used in this experiment first undergo a 24 hour compression that will compress the stents to 50% of its original diameter. This compression allows the stent to fit within the inner sheath more easily.
Mount Stent on Balloon Catheter
Mount Stent on Balloon Catheter
After the stent has been compressed for 24 hours it can then be mounted onto our modified 12 mm diameter Boston Scientific balloon catheter. This dual catheter system will act as a plunger to keep the stent in place and ensure proper placement when deployed, and a balloon that will inflate the stent via a handheld hydraulic pump.
Inflate Balloon
Inflate Balloon
Once the stent is in place the sheath can be pulled back and the balloon catheter can be inflated to the size of the mock trachea which is a 1/2" ID PVC clear tube.
Retract Deflated Balloon
Retract Deflated Balloon
After the stent has been deployed the catheter is deflated and removed from the mock trachea.
Results
Results
Even though the mock trachea does not fully represent in vivo conditions as it is fairly rigid and no lubricants were used to simulate the moist environment of the trachea, the PVC tubing allowed us to observe all the steps of the deployment system. No breakages or distortion of the stent structure could be visibly observed under these fully expanded conditions. However, because the inner diameter of the larger tubing (mock trachea) was ½ inches, even under full expansion, our stent failed to contact the walls of the lumen. This made retraction of the balloon difficult, as the stent tended to continue adhering to this balloon rather than staying in place at its intended deployment location.
Copolymer Synthesis
Copolymer Synthesis
Problem Statement
Problem Statement
PCL biodegradation takes between 2-3 years. Blending PCL with PLA could allow for the biodegradation profile to be tuned while maintaining the mechanical properties.
PCL biodegradation takes between 2-3 years. Blending PCL with PLA could allow for the biodegradation profile to be tuned while maintaining the mechanical properties.
Key Questions:
Key Questions:
What PCL/PLA Ratio will yield the best results in terms of consistency, biodegradation profile, and mechanical strength.
Will the co polymer blend still be able to print within the capabilities of a hobby grade 3D printer
Experimental Workflow
Experimental Workflow
Pelletizing the Filament
Pelletizing the Filament
The first step in creating a co-polymer is to obtain pellets of PCL and PLA or create our own from the filament that is typically used in the 3D printing process. The pelletizer we used would take in the 1.75mm diameter PCL and PLA filament and chop them into uniform sized pellets that would be fed into the hopper of the Filastruder.
Prepping the Pellets
Prepping the Pellets
The pellets are divided into weight ratios of our control, 100% PCL, and the following PCL/PLA blends: 80/20, 70/30, 60/40. The pellets are then dried for a period of 24 hours to ensure little to no moisture is present to avoid the possibility of air bubbles and moisture being trapped in the co-polymer filament.
Melt Blending
Melt Blending
The Filiastruder is turned on and set to a melt blending temperature of 160 degrees C. Each of the weight ratios are fed into the hopper of the Filastruder that is mounted vertically on the wall to try and achieve a uniform diameter of the co-polymer filament. Between each weight ratio the Filastruder is cleaned out.
Results
Results
With the Filastruder mounted horizontally the extruded filament would not be very consistent and nearly impossible to use in the 3D printer
With the Filastruder mounted horizontally the extruded filament would not be very consistent and nearly impossible to use in the 3D printer
Vertically mounting the Filastruder yielded excellent results and could be used to print a stent
Vertically mounting the Filastruder yielded excellent results and could be used to print a stent
There was not a sufficient amount of co-polymer filament that could yield the production of an entire stent but qualitatively a stent can be produced. The filament used the same printing temperatures that is used with PCL.
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