About Me: I’m an 8th grade science teacher at F.A. Day Middle school in Newton. Before moving up to 8th grade I taught 6th grade in the same school for 10 years, and one year of freshmen Earth Science and senior elective at Framingham High School. I received my Bachelors of Science degree in Environmental Geoscience at Boston College, where I minored in Environmental Studies and Secondary Education.  I loved BC but it didn’t have an engineering program – I am getting to see so many cool labs I’ve never been in before! I am very excited for this research experience to deepen my own understanding of the research process and take ideas back to my students.  I am getting exposed to real engineering projects and taking so many notes!  In addition to teaching, I coach cross country and track, and I’m currently the president-elect of the Massachussetts Association of Science Teachers. In my free time I am training for a half marathon in the fall and planning my wedding for next summer.

 

About the Lab:

This summer Sam Simmons and I are trying to build and test a smart catheter to measure pressure during a thrombectomy to treat ischemic strokes. Currently, the technology to help remove a blood clot blocking blood flow to the brain involves suction from a catheter under x-ray visualization. The end of the catheter is very tiny and the task of ensuring that the catheter is directly on the blood clot is difficult. If the catheter is not in the correct position to suction the clot away, the artery can collapse. There are also scenarios where the clot gets jammed during removal attempts.

The hope with a smart catheter is that the pressure readings can provide feedback during surgery to help doctors determine the placement of the catheter relative to the clot. We want to assemble the smart catheter, and then test it with the bench-top testing set up to determine if it can accurately measure pressure in the cardiovascular system and if its readings can successfully prevent arterial collapse.

First we are going to assist with ongoing efforts to develop a protocol to mount the pressure sensing fiber optic cable inside of the catheter that would be used for suction. This involves testing different adhesives and using the microscope to visualize the fiber optic cable’s orientation. Once successful, we will arrange the bench-top testing set up with phantom silicone arteries and hydrostatic pressure to simulate blood from the heart.

The goal will be to determine if the pressure from a blood clot before, during and after removal can be successfully measured. We will attempt to collapse the phantom arteries to see if pressure differences are observable.  Our analysis could help provide proof of concept for the smart catheter that could later be refined into a product safe to use in surgery.

 

Project Title: Engineering Bench-Top Testing of Interventional Devices for Cardiovascular Diseases

Weekly Updates:

Week 1:  (up to July 3rd)

In our first week, we received an introduction to the lab we’ll be working in and got to meet most of the graduate, undergraduate, and Mass Academy students working in the lab this summer. We got a nice overview of all of the different research projects taking place in the Medical and Manufacturing Innovation (MedMaIn) Lab. Professor Zheng and Brianna Raphion, our graduate student mentor,  helped us understand the smart catheter project. We got a sense of the overall goal, what progress has been made so far, and what roadblocks were still in place. We talked through the scope of our work this summer and what piece Sam and I could be working on to contribute to the overall project.

Our first task is to work on developing a protocol to adhere the fiber optic cable in the right orientation inside the catheter. The fiber optic cable needs to be 2mm from the distal end of the catheter, with the pressure sensing bubble aimed directly at the center of the catheter, and as much of the catheter open as possible to maintain flow. This has so far proven challenging for the lab! Brianna said they have been working on it since December with no luck. We looked into the material that the catheter and fiber optic cable are made out of in order to determine what adhesives will work best.  We learned that the inside of the catheter is lined with PTFE, or Teflon, so it is naturally hard to stick to! Brianna helped us order a lot of different adhesives to try. Next week we will compare them and see if any can stick to our nonstick surface!

Caption:Using the Amscope microscope to see the angled tip of the fiber optic cable. Its orientation will matter when we adhere it to the inside of the catheter.

Week 2:

Our time in the lab this week has been a productive one for the development of the Smart Catheter! This week started off with Sam and I testing a bunch of glues to see which adhesive would best stick the fiber optic cable to the inside of sample catheter. We had the idea to try to etch the surface (basically just scratch it up) after researching how anyone has successfully glued to Teflon. That worked very well, but it was much easier to etch the plastic tubing we were practicing on than the actual mesh-lined catheter.  Thinking that etching the catheter might deform it, Sam and I tried to 3D print a holder of sorts to keep the catheter’s shape. Our models weren’t actually all that helpful, but it was cool to try to teach ourselves how to use the 3D printer. We had never used SolidWorks before.

On a positive note, we might be able to avoid etching the catheter at all if we use tape! I was able to get a few practice pieces to stick with blue tape we found. Sam was able to help me the next day actually align the fiber optic cable properly.  It is a very delicate 2 person job to use the tweezers under the microscope. We’re aligning a glass cable the diameter of fishing line to the inside of a 2mm tube in a specific orientation. It’s tough to see and to manipulate but we practiced until we successfully adhered a bunch!

We have two next steps: first is to practice inserting the fiber optic cable in the opaque real catheter. (Our practice tubing is clear and easier to see). We ordered hollow needles that will hopefully help with insertion, but we need to work out the exact process. Our second step is to make “phantom arteries” with silicone in a mold under high pressure.  We learned in our first whole-lab group meeting that we have a recipe to “cook” a blood clot for testing later. Once we get our pressure sensor attached to our catheter, and a system of phantom silicone arteries set up, we can test it with a “real” blood clot. We are optimistic that hopefully we will be able to apply our protocol to make the real smart catheter next week! I can’t wait to run tests on it.

• Week 3:

We made some progress in week 3! We got to meet with Professor Zheng and Brianna Raphino to strategize next steps after successfully adhering a few prototypes. We were given a tour of the Fiber Optic Lab in Gateway and introduced to the collaborators providing the fiber optic sensor. We learned a lot more about the inner workings of our sensor and got to see the equipment used to produce it and the system we’ll eventually use to collect data.  In this lab tour we learned that the real fiber optic cable is actually coated in gold, so it will be a bit easier for us to see in the clear sample catheter. That was a helpful development.

After working on glue for the past few weeks, now we are transitioning to testing the suction part of the catheter. We will be using a water tank to submerge the phantom arteries we’ve been making. Our goal will be to model the 4 scenarios the team would like to show: a successful clot suction, an artery collapse, the clot breaking apart, and a clot jam. Playing the roll of our blood clot at first will be tofu in various degrees of firmness.

We met with two new undergraduate students who have been involved with the project at various stages. One had experience with making phantom arteries, and was able to give us feedback on procedure. Unfortunately his recommendation was to keep them setting longer, which will create some delay. We hope to have more molds printed to maybe speed up the process. We also tried attaching the first phantom artery to water simulate blood pressure. It completely blew up like a water balloon! We have a different type of silicone to try that more closely mimics the material properties of a real artery. Hopefully that will help it stand up to the blood pressure needed to create an accurate model.

 

• Week 4:

 

• Week 5:

 

Our Final Poster: