A new research of the International School of Advanced Studies (SISSA), revealed a new approach for studying neuronal activity: i nanometer photodiodes. This new methodology can be exploited for fundamental research on the nervous system and for the development of innovative therapies for neurological diseases.
The results of the study have been published in the scientific journal Science Advances.
Nanoscale photodiodes: this is how they work
A shock of light to modulate the activity of a single neuron in real time: this is how the innovative nanometer photodiodes work. The technique was developed by the team of researchers coordinated by Professor Laura Ballerini at SISSA in Trieste, in collaboration with the University of Chicago and Cambridge.
When activated with an infrared ray, nanoscale photodiodes of nanoscale precisely send an electrical message to the nerve cell to which they are bound, regulating their function. The effect of the stimulation can then be extended and amplified to the surrounding neuronal network by virtue of their synaptic contacts.
Functioning like a real electrode, but with a non-invasive and selective approach, these nanotechnologies could be extremely useful for basic research, to investigate in depth the dynamics of the nervous system, but also to develop new targeted therapies for neurological diseases. .
“To investigate the functioning of the nervous system, there is now a great deal of interest in technologies that need to be both very precise and non-aggressive. Our strategy goes precisely in this direction. Unlike what we have explored so far, where metal electrodes or the optogenetic combination of genetic manipulation and optical techniques, we have pursued a new, more specific and less invasive approach “, explained Professor Ballerini together with her collaborators, Denis Scaini And Mario Fontanini.
During the research, the SISSA group of scholars exploited innovative nanometric photodiodes, developed by the University of Chicago, capable of binding to the surface membrane of nerve cells: “Nanometric photodiodes light up when they are illuminated with infrared light”, explained the team of scientists: “In this way they can act electrically on the nerve cell, activating it. This is extremely useful for research purposes because it allows us to see what role a certain neuron plays in a certain process and, since the infrared is able to penetrate into the tissues, it modulates its activity from the outside in an agile and non-aggressive way ” .
But how can the nanoscale photodiodes be transported to the neuron the research team would like to analyze? Thanks to an ingenious mechanism developed in collaboration with the group of Ljiljana Fruk of the University of Cambridge: “The photodiode is linked to an antibody that works like a courier that picks it up and hooks it exactly where we want. This is because the antibody recognizes with great specificity a structure that we know is on the surface of the target neuron ”.
Working in the laboratory on explanted sections of the spinal cord, the SISSA team of scholars focused on the study of the sensory neurons involved in pain pathways: “We realized that nanometric photodiodes have the cap is able to selectively stimulate individual cells, allowing us to activate single neurons with functional roles, such as excitatory or inhibitory, ”the researchers specified.
“By activating an excitatory neuron on the dorsal spinal horn with the photodiode, we witnessed an amplification of the pain signal. Conversely, by acting on an inhibitory neuron, the opposite effect was obtained: the amplification of the pain signal was deactivated ”, added the SISSA research team.
Interestingly, the research also shows that acting on a single neuron can have a much broader effect, affecting the activity of an entire area: “This is exactly what we have verified: by stimulating a target neuron we can modulate the response of the ‘whole circuit, and this is very interesting for a variety of reasons, ”the researchers added.
“Thanks to its functionality and efficiency, this technique, so far developed only in vitro, could allow us to define neurosensory circuits in a very sophisticated way, obtaining very detailed information on the role played by individual nerve cells in the various mechanisms. This in-depth knowledge would consequently make it possible to design more and more specific therapeutic approaches at the level of the spinal cord ”, concluded Dr. Laura Ballerini.
As for neurological diseases in Italy, the figures are not very reassuring: 150,000 new cases of Stroke every year, with about 800,000 people who have survived the stroke but who bear the signs of disability; 300,000 patients with Parkinson’s disease; 120,000 those who today are affected by Multiple Sclerosis; 5 million people suffering from migraine, especially women and 800,000 those suffering from chronic migraine, with constant pain for more than 15 days a month. Up to 1 million people with mental impairment.
Professor Gianluigi Mancardi, President of SIN and Director of the Neurological Clinic of the University of Genoa, declared: “In the face of these numbers, the challenge of Italian neurology for the future is really demanding and a common effort will be needed to maintain scientific levels and improve health care levels. in the neurological field. If on the one hand, in fact, we are in third place in Europe and in seventh in the world for the number of scientific publications in neurology, on the other hand the quality of medical care, albeit at a good level, has to deal with modest investments. in health, research and training in our country “.
Professor Alfredo Berardelli, President of the Congress and Director of the Department of Human Neuroscience at La Sapienza University of Rome, intervened saying that: “Today the neurologist has new weapons available both from the pharmacological point of view, thanks to the recent discovery of new monoclonal therapies, and from the point of view pathophysiological view on the role of the cerebral motor cortex. We can also benefit from digital innovation that allows for remote monitoring of the evolution of the disease “.
For all these reasons and for the alarming numbers affecting the diagnosis of neurological diseases, the new approach with nanometer photodiodes that precisely examine neuron activity becomes an important hope for those suffering from these diseases.
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