New pacemaker that optically stimulates cardiac cells developed

Research team led by Prof. Hong-Gyu Park publishes findings in Proceedings of the National Academy of Sciences.

▲Prof. Hong-Gyu Park (Korea University), Jungkil Kim (Korea University), 

Kwang-Yong Jeong (Korea University)

The research team led by Prof. Hong-Gyu Park from the Korea University (KU)-KIST Graduate School of Converging Science and Technology and the Department of Physics, Korea University, worked with the research team led by Prof. Bozhi Tian in the Department of Physics, the University of Chicago, and developed a new pacemaker that can optically stimulate cardiac cells for cardiac pacing or resynchronization. Their joint research findings were published in the globally renowned Proceedings of the National Academy of Sciences (PNAS) on December 11, last year.

- Authors: Prof. Hong-Gyu Park (corresponding author, Korea University), Bozhi Tian (corresponding author, The University of Chicago), Jungkil Kim (co-author, Korea University), Kwang-Yong Jeong (co-author, Korea University)

- Title of the Article : Optical stimulation of cardiac cells with a polymer-supported silicon nanowire matrix, Proceedings of the National Academy of Sciences (2018). doi: 10.1073/pnas.1816428115

Cardiac conduction disorders caused by abnormalities in the heart’s electrical conduction system can be a fatal cardiovascular disease. However, the current treatments for these disorders, such as pacemakers, are bulky, rigid and invasive.

The new device developed by the joint research team uses a biocompatible polymer–silicon nanowire composite material. The silicon material forms tiny nanowire solar cells that stimulate the cardiomyocytes they are attached to by inducing electrochemical reactions from light pulses, while the polymer structure provides support by surrounding the heart in the form of a thin mesh.

When a small laser beam scans across a region of interest, the targeted cardiomyocytes are stimulated to beat at the same frequency as the laser pulses. Laser scanning operates the device more effectively than directly targeting one spot, and minimizes cardiac cell damage. Furthermore, unlike current pacemakers, this approach can train cardiomyocytes to beat at a particular frequency. Although such training takes time, the cardiac cells continue to move for a while even after the laser stimulus is turned off.

The new pacemaker is still in the initial stages of development. However, if fully developed, the device is expected to be inserted into the target area of the heart and the small optical fibers can deliver the laser pulses through a minimally invasive operation.

▲ Map of light absorption in regions of the mesh with silicon nanowires