Scientists at Karolinska Institutet have managed to build a fully functional neuron by using organic bioelectronics. This artificial neuron contain no ‘living’ parts, but is capable of mimicking the function of a human nerve cell and communicate in the same way as our own neurons do.

Neurons are isolated from each other and communicate with the help of chemical signals, commonly called neurotransmitters or signal substances. Inside a neuron, these chemical signals are converted to an electrical action potential, which travels along the axon of the neuron until it reaches the end. Here at the synapse, the electrical signal is converted to the release of chemical signals, which via diffusion can relay the signal to the next nerve cell.

To date, the primary technique for neuronal stimulation in human cells is based on electrical stimulation. However, scientists at the Swedish Medical Nanoscience Centre (SMNC) at Karolinska Institutet’s Department of Neuroscience in collaboration with colleagues at Linköping University, have now created an organic bioelectronic device that is capable of receiving chemical signals, which it can then relay to human cells.

“Our artificial neuron is made of conductive polymers and it functions like a human neuron”, says lead investigator Agneta Richter-Dahlfors, professor of cellular microbiology. “The sensing component of the artificial neuron senses a change in chemical signals in one dish, and translates this into an electrical signal. This electrical signal is next translated into the release of the neurotransmitter acetylcholine in a second dish, whose effect on living human cells can be monitored.“

Neurologial disorders

The research team hope that their innovation, presented in the journal Biosensors & Bioelectronics, will improve treatments for neurologial disorders which currently rely on traditional electrical stimulation. The new technique makes it possible to stimulate neurons based on specific chemical signals received from different parts of the body. In the future, this may help physicians to bypass damaged nerve cells and restore neural function.



Artifical neuron mimicks function of human cells

“Next, we would like to miniaturize this device to enable implantation into the human body”, says Agneta Richer-Dahlfors. “We foresee that in the future, by adding the concept of wireless communication, the biosensor could be placed in one part of the body, and trigger release of neurotransmitters at distant locations. Using such auto-regulated sensing and delivery, or possibly a remote control, new and exciting opportunities for future research and treatment of neurological disorders can be envisaged.”

About this neuroscience research

Funding This study was made possible by funding from Carl Bennet AB, VINNOVA, Karolinska Institutet, the Swedish Research Council, Swedish Brain Power, Knut and Alice Wallenberg Foundation, the Royal Swedish Academy of Sciences, and Önnesjö Foundation.

Source: KI Press Office – Karolinska Institute

Image Credit: Image is adapted from the Karolinska Institute video and is credited to the researchers

Video Source: The video is available at the karolinskainstitutet YouTube page

Original Research: Abstract for “An organic electronic biomimetic neuron enables auto-regulated neuromodulation” by Daniel T. Simon, Karin C. Larsson, David Nilsson, Gustav Burström, Dagmar Galter, Magnus Berggren, and Agneta Richter-Dahlfors in Biosensors & Bioelectronics. Published online April 22 2015 doi:10.1016/j.bios.2015.04.058

Abstract

An organic electronic biomimetic neuron enables auto-regulated neuromodulation

Current therapies for neurological disorders are based on traditional medication and electric stimulation. Here, we present an organic electronic biomimetic neuron, with the capacity to precisely intervene with the underlying malfunctioning signalling pathway using endogenous substances. The fundamental function of neurons, defined as chemical-to-electrical-to-chemical signal transduction, is achieved by connecting enzyme-based amperometric biosensors and organic electronic ion pumps. Selective biosensors transduce chemical signals into an electric current, which regulates electrophoretic delivery of chemical substances without necessitating liquid flow. Biosensors detected neurotransmitters in physiologically relevant ranges of 5–80 µM, showing linear response above 20 µm with approx. 0.1 nA/µM slope. When exceeding defined threshold concentrations, biosensor output signals, connected via custom hardware/software, activated local or distant neurotransmitter delivery from the organic electronic ion pump. Changes of 20 µM glutamate or acetylcholine triggered diffusive delivery of acetylcholine, which activated cells via receptor-mediated signalling. This was observed in real-time by single-cell ratiometric Ca2+ imaging. The results demonstrate the potential of the organic electronic biomimetic neuron in therapies involving long-range neuronal signalling by mimicking the function of projection neurons. Alternatively, conversion of glutamate-induced descending neuromuscular signals into acetylcholine-mediated muscular activation signals may be obtained, applicable for bridging injured sites and active prosthetics.

“Use of Brain MRI Atlases to Determine Boundaries of Age-Related Pathology: The Importance of Statistical Method” by David Alexander Dickie, Dominic E. Job, David Rodriguez Gonzalez, Susan D. Shenkin, and Joanna M. Wardlaw in PLOS ONE. Published online May 29 2015 doi:10.1371/journal.pone.0127939

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