About Me: My name is Michael Nixdorf, a WPI Graduate of 2025, and a Math/STEM educator in Worcester, MA. My time at WPI helped me recognize that one of my many passions is education and teaching. As a Worcester local and attendee of the Worcester Public Schools system, the inequity of STEM education and opportunities in Worcester is very apparent, with many programs being exclusive or monetarily unfeasible for some families. My goal as an educator is to help bridge the gap between STEM education/opportunities and our bright youth in the city of Worcester.
About the Lab: This research lab, led by Professor Yihao Zheng and graduate student Brianna Raphino, addresses a key challenge in thrombectomy procedures: the lack of reliable feedback for physicians regarding catheter positioning during blood clot removal.
Our focus is on developing and optimizing protocols to fabricate artificial arteries, enabling us to consistently measure pressure values around phantom vessels during simulated thrombectomies. This controlled experimental setup helps reduce external variables and improves the reliability and repeatability of our testing environment.
Project Title: Engineering Bench-Top Testing of Interventional Devices for Cardiovascular Diseases
Weekly Updates:
Week 1: This week introduced the project and our goals while highlighting the procedures involved in experimenting. We also familiarized ourselves with the lab and its equipment to ensure safety and consistency throughout the experiment. Below, you can see the workspace along with various tools and materials needed. Within this workspace, we aimed to create accurate and consistent blood clots and arteries to simulate the environment of cardiovascular procedures, such as thrombectomies.
 Figure 1: Model arteries that reveal the passage of blood flow |
Figure 2: Kyphoplasty tool, device to measure PSI |
 Figure 3: Sylgard 184 Silicone Elastomer Base and curing agent |
 Figure 4: Examples of mock soft and hard clot samples |
Figure 5: Prototype mold (left) and current mold (right) for arterial manufacturing |
 Figure 6: Diagram of 3-D mold and components |
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 Figure 8: Various perspectives of the 3-D mold |
Figure 7: Scale measurements of 3-D molds
Figure 9: Required tools to start the arterial procedure (heat gun, left), (silicone elastomer, center),(Mold lubricant, right) |
 Figure 10: Bench-top testing device for the procedure |
Week 2: This week began with familiarizing ourselves with the artery creation procedure. Following discussions and reflections from the previous week, we began using new 3D-printed molds, aiming to create more uniform and consistent arteries. We also calculated time variables for our temperature values to gauge how long we may need to cure our molds, given the plastic’s critical melting point. This was achieved by using data from other curing times and temperatures, along with the power regression function in the Desmos Graphing Calculator. Ms. Deborah Baird and I began hands-on experimenting as well, getting accustomed to the process and conducting some trial-and-error runs to observe where our experiment could be optimized.
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Figure 11: Various stages of experimentation
Figure 13: Multi-mold with hardware |
Figure 14: Artificial Arteries made from Multi-mold |
Figure 15: Single mold with abysmal results |
Week 3: This week, we began mass-producing arteries with the mult-mold designs. With 5 molds to use, capable of creating 5 arteries each, we can produce around 25 arteries each day. Due to the high volume of arterial production, it became evident that we would need to create batch numbers that included all the metrics used to manufacture those particular arteries. We took note of the orientation when cured; in this case, it was vertical. We also clarified the type of mold we used, which is the multi-mold. After which was the date and time the silicone was poured into the mold. The next data piece was whether we used the pre-mix silicone or the manual mix, followed by the vacuum chamber readings used to pull out any excess air.
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Figure 16: Trial 1 with data label
Figure 17: Trial 1 with example artery|
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Figure 18: Trials 11 and 12, the last trials of this week
Figure 19: Vacuum chamber used to remove excess air Figure 20: Shelf of molds with data labels (enhanced by “Lets Enhance.io” AI) |
Figure 21: Mold being opened with silicone attached to center rods (enhanced by “Lets Enhance.io” AI) |
Week 4: After creating a sound protocol, my team and I got right to work manufacturing more arteries this week. Finishing last week at trial 12, we made significant progress in understanding the best ways to remove arteries while preserving their integrity. This week, we have added plenty more batches, now at batch number 30, to finish the week. Although our volume of batches continually grows, we still face inconsistencies in certain areas due to the ratio mixtures. This week has been spent tinkering with the ratio mixture to find what works best, but also what aligns with the scholarly articles that have been published. Our goal is not only to create consistent arteries but to keep them aligned with the same material and physical properties of previously cited works. This has been a challenge due to the ratio feeling “stickier” and less valuable. We aren’t sure if the silicone needs more curing time or if it needs to be assisted with heat, but this is something we are figuring out this week.
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Figure 23: Sylgard base and curing agent, ingredients of silicone artery |
Figure 22: Ratio Mixture Figure 24: Batches of Arteries sorted by 10 each group, 1-10, 11-20, 21-30 |
 Figure 25: All 30 arteries spread out on the counter-top |
Week 5: After creating an abundance of arteries, we have moved on to using the arteries. This week, we began trialing ways to keep the arteries inflated after pumping them up with air. Our goal was to ensure that our system did not leak any air. We’ve also developed a technique of filling arteries with water to find any possible punctures or holes in the system. After doing so, we conducted many trials to find a constant pressure reading that would be ideal for each artery during observation. We have also begun figuring out the best and most effective method to take photos of our artery to gather measurements. We have a USB-connected camera that can be utilized via the Windows Camera app, and it is easy enough to use, but it has a problem with clarity and magnification. The setup for the camera is also very limiting. Given that it is on a tripod, we have had to work around the tripod, in hopes of getting clearer and magnified images, but this does limit our ability to take photos. We moved on to getting the Amscope microscope working and operational to enhance our photographic process, and this has significantly optimized our photo process. We have taken
Figure 26: Kyphon Pressure syringe, hemostat, compression ring, connecting nozzle, and medical-grade high-pressure lines (PVC) |
Figure 27: USB camera configuration and setup |
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 Figure 29 : Surface mold with measurements and labeled artery |
Figure 28: Amscope Microscope setup Figure 30: Surface mold with artery, nozzle, and compression rings |
 Figure 31: Surface mold with artery, compression rings, and a 5mm plug |
Week 6: This week, we prioritized data collection and finding results for our arteries. Our goal was to be able to measure the exterior width and compare these measurements with other batches. We observed and took measurements of each artery a total of 24 times, with three measurements per 2 cm, then rotating the artery and repeating the process. The procedure involved laying the artery flat on our dark surface, which is to ensure visual contrast, so observations can be clear. After 6 total measurements were recorded for each section, the artery was moved over 2 to 3 cm and measured again. After this measurement, it was rotated so that the seam of the artery was facing upward, and another 12 measurements were taken, 6 in one location and another 6 that were 2cm over. Totaling 24 measurements for each artery, this gave us a rough idea of how consistent our arteries would be. This process was accomplished via an Amscope microscope and Amscope software. This allowed us to look at each artery with incredible magnification, but also measure each artery’s width accurately and precisely. Using the microscope also required calibration. This involved using a physical ruler and placing it under the microscope’s vision, and manually clicking the start and end points of the centimeter. This allowed the software to understand the full value of a centimeter and give accurate measurements when observing each artery. This method was much more effective and efficient than the USB camera mentioned last week due to the ease of use and setup, accuracy and precision for measurements, and overall quality of the photos being taken.
 Figure 32: Artery Consistency |
 Figure 33: Initial width vs Final Width |
 Figure 34: Images of an inflated artery from batch 7 |
 Figure 35: Images of a static artery from batch 7 |
Final Poster:
WPI_RET_2025_Poster_Baird_Nixdorf_48x36
Lesson Plan:
https://docs.google.com/document/d/1QEBs3ZGYHeYwP3FmBB5qQRx0-D3DayGdNJ1TOKFnfRw/edit?usp=sharing