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Magnificent Metal

"Necessity is the mother of invention."

August 2006

by Natalie Gutierrez

That saying rings loud and clear with Health Science Center faculty physicians who treat patients suffering from serious illnesses and trauma every day. Faculty members see the need for better treatments, new technology and advanced health care, and they take it to heart - literally.

In 1988 Julio Palmaz, M.D., radiologist who is now the Ashbel Smith Professor at the Health Science Center, gained a patent on a tiny device he invented that would impact the world like no one had ever imagined. The Palmaz stent, a tiny wire-mesh, tube like scaffold, is now used in 2 million patients worldwide annually to repair clogged arteries near the heart and elsewhere in the body.

"This treatment is now commonplace, but it was unknown 25 years ago," Dr. Palmaz said. "Prior to stenting, the main treatment for opening constricted arteries was balloon angioplasty or bypass surgery." The stent has revolutionized the management of coronary artery and peripheral vascular disease.

Dr. Palmaz and Steven R. Bailey, M.D., professor of medicine and radiology, have discovered a method of building a superior stent and enhancing other biomedical surgical devices in the process.
Making Metal
Making Metal

Instead of the traditional method of cutting and welding various pieces of metal together to create a device such as a stent, Drs. Palmaz and Bailey use a three-dimensional process called "sputtering." The process is like an atomic pinball game, in which atoms and ions collide in an airtight chamber until they begin to adhere together to create a pure nickel titanium metal alloy.

The sputtering process has been used in semiconductor manufacturing of computer chips and other electronic devices since the 1980s, but this is the first time that it has been used to form pure metals and to create biomedical devices.

"Because this process allows us to create metals from the atom up, we can make metals purer and stronger than ever before," Dr. Bailey said. "In addition, we can fashion metal devices as large or as small as we need them and can shape them in forms never before possible."

Health Science Center faculty physicians have perfected the art of building better biomedical devices. The heart valve and stent are just the tip of the iceberg.
Health Science Center faculty physicians have perfected the art of building better biomedical devices. They’ve put a twist on a traditional method to manufacture metals, atom by atom, making them pliable, purer, stronger and smaller than ever before. The heart valve and stent are just the tip of the iceberg.

Stents are normally about half an inch long, or the size of a thumbnail. However, Drs. Bailey and Palmaz can now create a stent with a membrane wall that is smaller than half the width of a human hair. Although the stent wall is so thin it can’t be seen with the human eye, it retains much of the strength of the larger stent. Dr. Bailey said stents of this size will become invaluable in surgical procedures used to stop bleeding in small blood vessels in the brain, intestines, uterus or other parts of the body that previously were impossible to reach with traditional methods.

"The list of new and improved biomedical surgical devices that we will be able to create using our new method continues to expand," Dr. Bailey said. "These will be the next generation of interventional and endovascular tools."

Better techniques, better tools

Last year, Dr. Bailey became one of the first cardiologists in the nation to use a percutaneous (through the skin) heart valve repair system to treat a patient with mitral valve regurgitation (leakage). Dr. Bailey hopes to use this same procedure to perform heart valve replacement surgery.

"With our method of manipulating metals, we hope to be able to make heart valves small enough to fit through tubing and to be guided through an artery in the leg to the location where the heart valve needs to be replaced," Dr. Bailey said. "Opening the chest wall will not be necessary. This is likely to result in shorter hospital stays and quicker recovery time for patients."

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