Using Shape Memory Polymers to Treat

Cerebral Aneurysms

Dorothy Ringer SumnerAldine 9th Grade School, Aldine ISD

Dr. Duncan MaitlandAssociate Professor, Department of Biomedical

Engineering,Faculty Mentor

Dr. Duncan Maitland Refining development

of device using shape memory polymer foams to non-surgically treat aneurysms.

Developed research at Lawrence Livermore.

Chose Texas A&M Institute for Preclinical Studies (TIPS) because of facilities.

Texas A & M Institute for Preclinical Studies (TIPS)

Large animal research facility, founded 2007,

Supports research in medical device development.

Trains students in engineering, science and veterinary medicine.

Facilitates preclinical testing.

1 of 7 labs in the country conducting this research.

Relevance of Research 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, head trauma and birth defects.

Surgical Treatment of Aneurysms

•Micro-vascular Clipping (1937)

• Completely close off with a metal clip to prevent bleeding or rupture • protecting nearby brain tissue from damage.•Risks: -anesthesia -cut into skull

Non- Surgical Treatment: Coils

Embolic Coiling, (1990’s )

Shape Memory Polymers (SMP) Foams

SMP’s are polymers that remember their shape.

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

Embolic Shape Memory Polymer (SMP) Foams

SMP Mechanism

• Polymer foam inserted through catheter in its compressed form.

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

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

Deform at High Temperature(above glass transition temp)

Heat above glass transition

Cool below glass transition and Unload

Shape Fixity Shape Recovery

A B BB A

Deform Cool Unload Heat

Permanent Shape at High Temp

TemporaryShape at Low Temp

SMP Deformation Process

Why SMP Foam Therapy Shaped for faster and more complete

occlusion of the aneurysm. Lower and more uniform stresses to the

aneurysm wall, thereby decreasing the risk of hemorrhage.

Faster healing time due to structure of foam.

Research Assignment To become familiar with the tools and

techniques used in developing a shape memory polymer (SMP) foam plug device for the treatment of cerebral aneurysms from research implementation studies to completed device by modeling the research activities conducted in the biomedical device lab.

Research Activities

Develop 3-D model of an aneurysm. Create various SMP’s and investigate

their properties. Develop model of SMP foam device.

Research Activities

Acrylic SMP

Dip coating brass rods for stents

Creating 3-D model of aneurysm from MRI to design SMP foam device.

Summary

To become familiar with shape memory polymers and other biomaterials their use in medicine and industry.

Incorporate engineering concepts into my biology curriculum.

Relate the real world applications of engineering in biology and other science disciplines.

Acknowledgements

TAMU E3 Program National Science Foundation Nuclear Power Institute Texas Workforce Commission Dr. Duncan Maitland Mr. John Horn