For a long time, scientists around the world have been trying to mimic natural systems such as the human anatomy and plant structure for various medical reasons. They have already been successful at creating fully lab-grown and microscopic-scaled replicas of organs or body parts from stem cells, which are now called “organoids”. In despite of all mentioned improvements, could we yet manage to say that humans are capable of recreating cells of their most complex organ? As far-fetched as it may sound, the response to this question seems to be positive. And to be even more astonished, we can take a look at how it has been done.
Firstly, to fully understand, it is best to mention what an artificial neural network is and why we needed it in the first place. To initially understand their concept, we can benefit from our observations on a daily basis. For example, inside the computers that we use every day, there is a huge net of systematic connections which operate with electrical impulses. Our brains work in a very similar way. It consists of a giant network of neurons constantly transferring information through biological signals. Thus, an artificial neural network or a simulated neural network (SNN) can be best described as a mass of node layers (which have a specific weight and a threshold) basically sending signals between each layer in order to replicate the way an animal brain operates. Also, in the future, this innovation can be used to encourage other improvements in the field of artificial intelligence, medicine, or more specifically in medical nanotechnology.
Concerning this agenda, many projects are still being conducted; however, the first attempt that paved the way for all other research was led in 1943 by Warren McCulloch, an American neurophysiologist, and Walter Pitts, a logician on computational neuroscience. Thereafter, approaches to the matter became more specifically targeted and the threshold logic was found, and since then, science enthusiasts have been following the developments on this issue. We can say that the most remarkable breakthrough has been achieved in the late 2010s by a research group at Laboratory for Organic Electronics (LOE) at Linköping University. The team led by Simone Fabiano was one of the first groups to create organic electrochemical transistors (OECTs) based on the n-type conducting polymers which managed to meet several characteristics of a biological nerve. The OECTs had many fascinating aspects to them since they could conduct negative charges, operate at low voltages, and switch speeds fast and efficiently while also being biocompatible. Later on, the group kept on improving the OECTs so that they could print electrochemical circuits to obtain thousands of transistors which would eventually become the new artificial organic nerve cells, the c-OECNs.
Simone Fabiano, the principal investigator and an associate professor at Linköping University, stated that one of the biggest obstacles that the team faced during the process was the difficulties of incorporating ion modulation, which was not evidently achieved by traditional artificial nerve cells, as they could not communicate through ions. However, the new artificial cells named “c-OECN” are created by the same researchers and are capable of operating through ions, which shows that they have a significant similarity to the biological neuron cells. The ions now control the voltage in the circuit which allows the current to flow and the frequency of spikes of electricity, which mimic the biological signal, to cause a reaction.
Photo: The lead author of the study making the chemical transistors, Credit: Thor Balkhead, Linköping University
The research group also collaborated with other scientists to conduct their experiments with their newly-found systems. In cooperation with Karolinska Institutet, the new c-OECNs have been connected to the vagus nerve of mice which carries an extensive range of signals. Then it has been concluded that the artificial neurons, could stimulate the nerves of the mice and cause some changes in their heart rates.
To conclude, the results of the mentioned experiment and the whole research, gave hope to some, as it could later on lead to other improvements in the field of medicine such as various new types of treatments for metabolic diseases and threats to the immune systems. That also means it is now safe to say that all of the mentioned aspects give us enough reasons to consider the research to be promising, and to be a milestone in this field.
Edited by: Bilge Öztürk
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