In a novel approach, a fresh study at SISSA uses technology that may activate individual nerve cells with a light impulse. This targeted, non-invasive approach may be used for fundamental studies in to the nervous system and also the development of innovative therapies for neurological diseases
A jolt of light to modulate the experience of an individual neuron instantly: This is one way innovative nanometric photodiodes work, the main topic of a new study published in Science Advances. The technique originated by Professor Laura Ballerini’s team at SISSA in Trieste, in collaboration with the Universities of Chicago and Cambridge.
When activated having an infrared ray, photodiodes of nanometric scale send a power message to the nerve cell to that they are bound, regulating its function. The result of the stimulation may then be extended and amplified to the encompassing network of neurons in virtue of these synaptic contacts. Working such as a real electrode, but with a noninvasive and selective approach, these nanotechnologies can be hugely useful for preliminary research, to research in-depth the mechanisms of the nervous system, but additionally to build up targeted therapies for neurological diseases.
Nanometric photodiodes: Here’s how they work
“To research the functioning of the nervous system, there’s now great fascination with technologies that must definitely be both very precise and non-aggressive. Our strategy goes precisely in this direction. Differently from what explored up to now, where metal electrodes or the optogenetic mix of genetic manipulation and optical techniques were used, we pursued a fresh, more specific and less invasive approach,” say Professor Ballerini and her collaborators, Denis Scaini and Mario Fontanini.
In the analysis, the SISSA research group used innovative nanometric photodiodes, produced by the University of Chicago, which can handle binding to the top membrane of nerve cells. “The photodiodes light when illuminated with infrared light,” explain the scientists. “In this manner they are able to act electrically on the nerve cell, activating it. That is extremely ideal for research purposes since it we can see what role a particular neuron plays in confirmed process and, since infrared can penetrate tissue, modulate its activity from the exterior within an agile and non-aggressive way.”
But how can you obtain the photodiode to the neuron you intend to study? Because of a nifty little mechanism developed in collaboration with Ljiljana Fruk’s group from University of Cambridge: “The photodiode will an antibody that works such as a courier taking and hooking it wherever we desire to. It is because the antibody recognizes with great specificity a structure that people know is at first glance of the prospective neuron.”
New technology with an enormous potential
Employed in the laboratory on explant parts of the spinal-cord, the SISSA staff centered on the analysis of the sensory neurons involved with pain pathways: “We realized our method can selectively stimulate individual cells, allowing us to activate individual neurons with opposite functional roles, e.g., excitatory or inhibitory,” explain the researchers. “By activating an excitatory neuron on the spinal dorsal horn with the photodiode, we witnessed an amplification of the pain signal. Vice-versa, by functioning on an inhibitory neuron the contrary effect was obtained: the amplification of the pain signal was powered down.”
Interestingly, the study also implies that acting on just one single neuron might have a much wider effect, affecting the experience of a complete area. “This is just what we verified: by stimulating a target neuron we are able to modulate the response of the complete circuit, which is quite interesting for several reasons,” say the researchers.
“Because of its functionality and efficiency this system, which has up to now only been developed in-vitro, could allow us to define neurosensory circuits in an exceedingly sophisticated way, obtaining highly detailed info on the role played by individual nerve cells in various mechanisms. This in-depth knowledge would consequently allow increasingly specific therapeutic methods to be designed at the spinal-cord level,” concludes Laura Ballerini.
More info: Agnes Thalhammer et al, Distributed interfacing by nanoscale photodiodes enables single neuron light-activation and sensory enhancement in 3D spinal explants, Science Advances (2022). DOI: 10.1126/sciadv.abp9257. www.science.org/doi/10.1126/sciadv.abp9257
Citation: When light may be the switch: Nanometric photodiodes to review the experience of neurons (2022, August 12) retrieved 14 August 2022 from https://medicalxpress.com/news/2022-08-nanometric-photodiodes-neurons.html
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