Researchers at Delft University of Technology (TU Delft, Netherlands) have discovered a new way of visualising electrical signals in living cells. Using nano-antennas, they can amplify the fluorescence of luminescent proteins, enabling changes in cells to be monitored more accurately. The technique could be particularly important for research into nerve cells. The electrical activity, which could previously be visualised using fluorescent proteins, is now more pronounced and easier to measure.
The researchers are thus combining two technologies that, until now, have mainly been used separately. Fluorescent proteins light up when a nerve cell’s electrical voltage changes. By placing nano-antennas next to them, the emitted light is amplified. This offers researchers a new way to monitor processes in living cells. The study has been published in *Advanced Materials*.
To track signals in the brain, both high resolution and rapid imaging are required. “Existing methods for monitoring voltage in cells often do not produce enough light or do not respond quickly or strongly enough to the tiny electrical pulses in synapses,” said lead researcher Daan Brinks.
Voltage-sensitive proteins
Lead authors Marco Locarno and Qiangrui Dong achieved a breakthrough by placing nano-antennas close to luminescent, voltage-sensitive proteins. This amplified the light up to six times, enabling researchers to track processes in living mammalian cells much more accurately. The cells remain alive and function normally whilst being studied.
According to Brinks, the transition from nanophotonics to living cells proved technically complex. The nano-antennas must have a specific shape and size and remain chemically stable. Furthermore, they must be delivered to exactly the right location within the cell without disrupting it. To achieve this, the researchers combined computer modelling with chemical techniques and biological experiments. This approach made it possible to specifically link the nano-antennas to the voltage-sensitive proteins.
Reacting ten times faster
The researchers also discovered that the voltage-sensitive proteins not only glowed more brightly, but also responded approximately ten times faster to changes in electrical voltage. This came as a surprise. Previous attempts to increase the speed of these proteins through genetic modifications had yielded only limited gains. The presence of a nanoparticle proved to enable a much greater acceleration.
This opens up a new way of influencing how proteins function: not only by modifying their genetic properties, but also by attaching a nanostructure to them. According to the researchers, this approach could potentially be applied to other proteins as well, such as those involved in signal transduction or the transport of substances within cells.
Brain research
For brain research, the increased reaction speed means that electrical activity can be monitored on a smaller scale, right down to the level of synapses where neurons exchange information. The technology could therefore offer new opportunities to investigate how the brain processes information and what happens at a microscopic level during processes such as learning and memory.
Add ICT&health on Google
Show more content from ICT&health in Google Search.
