According to a study published in the Optical Society of America’s (OSA) Optics Express, a group of scientists at Osaka University in Japan, have created the world’s first optical pacemaker. The study found that powerful, but very short laser pulses can help control the beating of heart muscle cells. In fact, laser pulses cause the release of calcium ions within the cells, which forces the cells to contract. This technique provides a tool for controlling heart muscle cells in the laboratory, a breakthrough that may help scientists better understand the mechanism of heart muscle contraction. "If you put a large amount of laser power through these cells over a very short time period, you get a huge response," says Nicholas Smith, who led the research. One potential application of this technology is in studying uncoordinated contractions in heart muscle. Normally, heart muscles contracts in a highly coordinated fashion, and this is what allows the heart to pump blood through the vasculature. But in some people, this coordinated beating breaks down, and the heart twitches irregularly - a condition known as fibrillation. The new laser technique can destabilize the beating of the cells in laboratory experiments by introducing a beat frequency in one target cell distinct from the surrounding cells. This would allow scientists to study irregular heart beats on a cellular level and screen anti-fibrillation drugs. Outside the laboratory, exposing heart muscle cells to powerful laser pulses can have its drawbacks. Although the laser pulses last for less than a trillionth of a second, damaging effects can build up over time. Currently, this limits the possibility of clinical applications. This study was supported by the Japan Science and Technology Organization. For more information, visit: www.osaka-u.ac.jp/eng/ or www.osa.org