Image of the Day: Nanoscale Optical Probes

New nanoprobes allow researchers to study large-scale electrical activity of cells with greater precision.

Emily Makowski
Oct 24, 2019
ABOVE: False-color scanning electron micrograph of human stem cell-derived cardiomyocytes (purple) cultured on an electro-plasmonic nanoantenna array

Microelectrode arrays are used for monitoring bioelectric activity in neurons and cardiomyocytes, but their wiring has a narrow bandwidth for transmitting bioelectric signals. They also have limited spatial resolution and are hard to use for large-scale cell measurements. Researchers led by Ali Yanik, an electrical engineer at the University of California, Santa Cruz, have developed ultrasensitive nanoscale optical probes that can measure many individual cells simultaneously. Their work was published in Science Advances October 18.  

The new nanoprobes feature a nanoantenna array that allows researchers to read signals remotely instead of using wiring, bypassing the limitations of microelectrodes. The nanoantennae use light to detect electrical activity signals. “The electro-plasmonic nanoantenna has a resonance frequency that changes in response to the electric field, and we can see that when we shine light on it, so we can read the signal remotely,” Yanik says in a news release, adding that it’s “the same reason why the telecommunication industry moved to fiber optics. By converting bioelectric signals to photons, we will be able to transmit large-bandwidth neural activity optically.” The probes could someday be used in high-bandwidth brain-machine interfaces or to attach to and monitor specific cell types inside the body.

A typical microelectrode in an array (left) is about the same size as a cell and requires wiring, while the wireless nanoelectrodes (right) are much smaller than human stem cell-derived cardiomyocytes.

A. Habib et al., “Electro-plasmonic nanoantenna: A nonfluorescent optical probe for ultrasensitive label-free detection of electrophysiological signals,” Sci Adv, doi:10.1126/sciadv.aav9786, 2019.

Emily Makowski is an intern at The Scientist. Email her at