CARDIAC DISEASE AND TREATMENT DEVICES

Dorothy Ringer SumnerBiology Teacher

Aldine 9th Grade School, Aldine ISD

Enrichment Experience in Engineering E3Research Experiences for Secondary Math and Science

Teachers

Dr. Duncan MaitlandAssociate Professor,

Department of Biomedical EngineeringBiomedical Device Laboratory

Faculty Mentor

UNDERSTANDING ANEURYSMS Aneurysms are abnormal

widening or ballooning of blood vessels.

Prevalent in 5% of the U.S. population.

Not life threatening unless it begins pressing on the brain or ruptures.

30,000 people die or suffer neurological damage from rupture. (Stroke or subarachnoid hemorrhage)

Pre-existing conditions include hypertension, atherosclerosis, kidney disease, head trauma and birth defects.

SMP’s are polymers that remember their shape.

Can be compressed drastically and still retain original shape when acted upon by stimulus.

Biocompatible. Blood clots throughout the

porous foam and forms a layer of endothelial cells across the aneurysm for faster healing.

Lower and more uniform stresses on wall, lowers hemorrhage risk.

WHY SHAPE MEMORY POLYMERS (SMP) FOAMS THERAPY

SMP FOAM MECHANISM OF DEPLOYMENT

• Polymer foam is inserted through catheter in its compressed form.

• Laser light beam is shone through an optical fiber in the catheter.

• Laser hits the SMP cylinder, it expands and plugs the aneurysm as it returns to its original ball shape.

Embolic Shape Memory Polymer Foam Deployment

Model of aneurysm that has a dye added to view the laser as the SMP foam is being deployed.

Overview: This lesson unit introduces students to biomedical

engineering and the technology of shape memory polymers. As they create a device to deliver a compressed polymer to an aneurysm, testing its reliability and considering pros and cons, they learn about issues and materials that biomedical engineers consider in designing medical devices.

Students learn how a shape memory polymer can clot an aneurysm and direct blood flow through the artery. Using everyday items, each team of students designs and builds an SMP Deployment Device capable of plugging the aneurysm. Students develop a plan, build and test their system, and then evaluate the effectiveness of their and other teams’ efforts. Finally, they present their findings to the class.

UNIT CONCEPTS Circulatory diseases and treatment of organ systems

Chemical structure and properties of polymers

Engineering design

E3 PROJECT INSTRUCTIONAL PLAN

Day Topic Instructional Activities STAAR/EOC/TAKS

TEKS Resources

1 Circulatory System Disorders

Use power point to discuss the structure and function of the circulatory system, its disease.

Have student trace the path of blood through the heart to major areas of the body using anatomical models.

Discuss the diseases described in the power point and new research to treat aneurysms.

Discuss lifestyle changes a person with heart disease may benefit from.

Explain to students that they will design a device to treat aneurysms by simulating the technology described in the power point presentation and in their homework reading assignment.

Homework: Read handouts, Understanding Aneurysms and Properties of SMP’s

To discover how biology, technology and manufacturing are linked.

10)  (A)  describe the interactions that occur among systems that perform the functions of regulation, and defense from injury or illness in animals;

Power point:

Circulatory System and Disease.

Teacher developed handouts: Understanding Aneurysms andProperties of

SMP’s

E 3 PROJECT INSTRUCTIONAL PLAN2 Shape

Memory Polymers

Discuss the homework reading assignment.

Introduce shape memory polymers (SMP) using the power point presentation, Weird and Wonderful Polymers.

Read and discuss the procedures for making a SMP in the lab handout.

Students will complete the lab activity, Making a SMP in their collaborative groups.

Homework: Students will complete a chart describing the various uses of the SMP’s.

To discover howbiology, technology and Manufacturingare linked.

To practiceusing the scientific method by planning and carrying out valid tests, to problem solving, making assumptions, developing a design, testing a design.

2) (E)  Plan and implement descriptive, comparative, and experimental investigations, including asking questions, formulating testable hypotheses, and selecting equipment and technology.

Power point: Weird and Wonderful Polymers.Lab activity: Making a

Shape Memory

Polymer (see handouts for materials list) .

3 ShapeMemoryPolymers

Students will complete the Making a SMP lab by deforming the solid polymer and recording observations in their notebooks.

Demonstrate how the polymer sodium polyacrylate (found in diapers) absorbs liquid.

Explain to the students that they will use this substance as their SMP when creating their deployment device (some treatment therapies use hydrogels to fill aneurysms).

Pass out assignment, Design Your Own Polymer Delivery Device.

Read through assignment with students and assign their collaborative teams.

Students will brainstorm ways to create their device using the given material list.

Homework: Continue to brainstorm ways to create device and sketch model of design idea in notebook to share with team.

To discover how biology, technology and manufacturing are linked. To think creatively about the implications of a scientific discovery and how it could be put to use.

2)(E)  Plan and implement experimental investigations, including asking questions, formulating testable hypotheses, and selecting equipment and technology;

Teacher developed handouts: What is Sodium

Polyacrylate?,

Why Does

Polyacrylate

Absorb Water?, and Design

Your Own

Polymer

Delivery Device

(see handouts for materials list)

4 Designing a PolymerDeployment Device

Students will create an aneurysm with a straw heated to deform it.

Students will design device to treat aneurysm. The device must be able to allow a syringe of simulated blood to flow through the artery.

To practice using the scientific method by planning and carrying out valid tests, to problem solving, making assumptions, developing a design, testing a design.

2)(E)  plan and implement descriptive, comparative, and experimental investigations, including asking questions, formulating testable hypotheses, and selecting equipment and technology;

Design A

Polymer Delivery

Device(see handouts for materials list)

Day Topic Instructional Activities STAAR/EOC/TAKS

TEKS Resources

5 Designing a PolymerDeployment Device

Each team will test their device to see how it functions.

Each team will present their design and results to the class.

To practice using the scientific method by planning and carrying out valid tests, problem solving, making assumptions, developing a design, testing a design.

2)(E)  plan and implement descriptive, comparative experimental investigationsincluding asking questions, formulating testable hypotheses, and selecting equipment and technology;

Designing A

Polymer

Delivery Device

DESIGNING A POLYMER DELIVERY DEVICE

Lesson Focus: Aneurysms are abnormal widening or ballooning of

blood vessels. They are prevalent in 5% of the U.S. population. They are not life threatening unless one begins pressing on the brain or ruptures.

30,000 people die or suffer neurological damage from the rupture of an aneurysm. When this occurs it is referred to as a stroke or subarachnoid hemorrhage. People with conditions such as hypertension, atherosclerosis, kidney disease, head trauma and birth defects are more likely to develop an aneurysm. Aneurysms can be treated by cutting off the supply of blood to the aneurysm and allowing it to clot. Current research involves designing medical devices to deliver shape memory polymers to the aneurysm site, plugging it, and thereby, allowing uninterrupted blood flow through the artery.

Learning Objectives: To gain knowledge of biomedical engineering,

engineering design, planning, construction, teamwork, and working in collaborative groups.

Describe the engineering design considerations that go into developing quality medical devices.

List characteristics and features that are important for a medical device.

Analyze a prototype of a shape memory polymer deployment device and make suggestions for design improvements.

Materials: Clear plastic straws, aquarium tubing, gel capsules,

wire, paper clips, string, sodium polyacrylate, coffee stirrer, alcohol burner, hot plate.

Procedure: 1. Show students the power point presentation, “Using Shape Memory

Polymers to Treat Cerebral Aneurysms”. This may be shown in class, or provided as handout slides to read for the prior night’s homework along with the assignment.

2. Divide students into groups of 4 students, providing a set of materials per group.

3. Explain that students must work as a team to design medical device to deploy (deliver) a shape memory polymer in its compressed form to the site of an aneurysm and include in the design, a stimulus for the polymer to expand or actuate

4. Students discuss and develop a plan for their deployment device. They draw their plan, and then present their plan to the teacher or other teams.

5. The teams execute their plans. They may need to rethink their design, or even start over.

6. The teams will test their deployment device to see how it works. Students will measure how much simulated blood flowed through the artery and not into the aneurysm. The teams may test their systems three times and use the most successful test for their results.

7. Teams then complete an evaluation/reflection worksheet, and present their findings to the class.

PRETEST/ POST TEST QUESTIONS Which set contains

one natural polymer and one synthetic polymer? A. cellulose and starch B. polyethylene and nylon C. protein and starch D. protein and polyacrylate

A polymer that can return to its original shape after being deformed is called________.

A. plastic B. shape memory

polymer C. polyacrylate D. polyacetate

ACKNOWLEDGEMENTS TAMU E3 Program National Science Foundation Texas Workforce Commission Dr. Duncan Maitland, Faculty Mentor John Horn, graduate student

(Biomedical Engineering ) Ashwin Rao, graduate student

(Mechanical Engineering) Mary Biediger, lab partner