A new ultrasensitive nanoscale optical probe has been developed by the researchers at UC Santa Cruz that can monitor the bioelectric activity of neurons and other excitable cells.
This novel technology could help researchers better understand how neural circuits function at unexplored scales by measuring the activity of huge numbers of individual neurons at the same time.
The device could also help in the development of high-bandwidth brain-machine interfaces in the future.
The electrical activity of neurons is monitored using microelectrode arrays, but these cannot simultaneously address a large number of neurons. The technique also suffers from poor or limited spatial resolution.
Although optical biosensors already exist, many of these require genetic modifications to be made to cells so that fluorescent molecules can be inserted into cell membranes. This implies that these techniques cannot be employed in human cells.
However, this problem has now been overcome by using a novel nanoantenna loading mechanism based on concepts adapted from RF communications.
The researchers began by fabricating nanoscale plasmonic nanoantennas less than 100 nm in diameter and then coated them with a biocompatible nanoscale electrochromic polymer, poly(3,4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT: PSS), which is highly sensitive to a local electric field.
The new technique is fundamentally different from genetically-encoded voltage-sensitive fluorescence.