Biophan makes implantable laser

17 Jun 2002

A pacemaker incorporating the first implanted laser will allow patients to undergo diagnostic scans.

Laser-based pacemaker

US firm Biophan has developed a fiber-optic-based pacemaker that incorporates what it claims is the first laser to be implanted into the human body. The device will for the first time enable patients with pacemakers to undergo magnetic resonance imaging (MRI) scans.

"To our knowledge, this is the first implantable laser," said Mike Weiner, chief executive of Biophan. Around 600 000 pacemakers are implanted every year to treat a variety of conditions including epilepsy, acute pain and Parkinson's disease. Although the company's initial focus was on cardiovascular pacing, the device design would enable any pacemaker to be MRI compatible.

Current pacemaker designs include a 30 cm-long metal wire that connects the pacemaker to the heart. During an MRI, the wire can heat up causing damage to the blood vessels and heart. The wire also picks up radio interference, which can impair the pacemaker's performance. As such, the wearers of a conventional pacemaker cannot undergo an MRI scan.

This new pacemaker replaces the metal wire with an optical fiber. "The laser is enclosed and never touches the tissue. Light from the laser is transmitted along the optical fiber to the tip. At the tip the light hits a photodiode and is converted back to electrical impulses that are used to pace the heart. The overall device is about the size of a matchbox," explained Weiner.

The photodiode at the fiber tip also acts as a sensor measuring temperature, pressure and flow. "This device offers a mixture of diagnostics and therapeutics," said Weiner. The semiconductor laser used in the device is pulsed with a low duty cycle, maximizing the lifetime and efficiency.

Clinical trials are being explored with several major heart institutes.

"This is the first in what we see will be a revolution in bioscience and the convergence of biology and photonics. In the future we believe all implantable pacemakers will be photonic," concluded Weiner.