Lasers to create Arterial Stents and Longer-Lasting Medical Implants
Technology.am (Sept. 16, 2009) — Researchers at Purdue’s Center for Laser-Based Manufacturing are developing technologies that use lasers to create arterial stents and longer-lasting medical implants that could be manufactured 10 times faster and also less expensively than now possible.
One of the researchers’ techniques works by depositing layers of a powdered mixture of metal and ceramic materials, melting the powder with a laser and then immediately solidifying each layer to form parts.
Because the technique enables parts to be formed one layer at a time, it is ideal for coating titanium implants with ceramic materials that mimic the characteristics of natural bone, said Yung Shin, a professor of mechanical engineering and director of Purdue’s Center for Laser-Based Manufacturing.
They used their laser deposition processes to create a porous titanium-based surface and also a calcium phosphate outer surface, both designed to better match the stiffness of bone than conventional implants.
The laser deposition process enables researchers to make parts with complex shapes that are customized for the patient and this technique lends itself to the requirement that each implant be designed specifically for each patient.
The process creates a strong bond between the material being deposited and the underlying titanium, steel or chromium. Tests showed the bond was at least seven times as strong as industry standards require, he said.
The researchers also are developing a technique that uses an “ultra short pulse laser” to create arterial stents, which are metal scaffolds inserted into arteries to keep them open after surgeries to treat clogs.
The laser pulses last only a matter of picoseconds, or quadrillionths of a second. Because the pulses are so fleeting, the laser does not cause heat damage to the foil-thin stainless steel and titanium material used to make the stents.
The laser removes material in precise patterns in a process called “cold ablation,” which turns solids into a plasma. The patterns enable the stents to expand properly after being inserted into a blood vessel.