Understanding the mechanisms by which the brain functions is one of the most complex challenges in science. One important aspect is the electrical conduction of stimuli in nerve cells.
In order to study neuronal circuits, a sharp metal electrode is usually inserted into the brain to introduce a current. However, the response does not reflect the highly complex activation patterns of natural nerve stimuli. In addition, the direct current applied in this fashion causes damage to tissue through undesired electrochemical side reactions.
Collaboration between neuroscientists and nanomaterials researchers at Case Western Reserve University (Cleveland, Ohio, USA) has resulted in the development of a technique that is both gentler and elicits more natural nerve impulses. As reported in the journal Angewandte Chemie, the technique is based on a micropipette coated with semiconductor nanoparticles that activates neurons in brain tissue with visible or infrared (IR) light. In contrast to conventional electrodes, these photoelectrodes require neither wires nor electrical power.
The team led by Ben W. Strowbridge and Clemens Burda coated the interiors of extremely finely drawn-out glass micropipettes with lead selenide nanoparticles. Lead selenide is a semiconductor that is activated by IR light. As in solar cells, irradiation “catapults” firmly bound electrons out of the valence band and into the conduction band of the semiconductor, where they can move freely. This leads to charge separation and thus to an electrical potential. With a suitable laser, defined processes elicited by short light pulses set off corresponding electrical pulses in the micropipette. An electrical field is thus formed around the pipette, which can then be used by the researchers to stimulate neurons in rat brain samples with a high degree of time-resolution. Measuring electrodes could then be used to record the natural activation patterns of very similar nerve impulses.
Samples of the olfactory bulb (a region of the brain involved in processing smell) and the hippocampus (part of the cerebrum important in the transfer of contents from short-term to the long-term memory) were examined. Neither toxic effects nor damage to the nerve cells were observed after repeated stimulation.
By using these new photoelectrodes, the cooperation of nerve cells can be studied. However, therapeutic applications are also possible: the probes could be used to activate individual regions of the brain or damaged or cut nerves to restore function – without the need for disturbing wires.
Author: Clemens Burda, Case Western Reserve University, Cleveland (USA), http://www.case.edu/nanobook/pages/faculty/cburda.htm
Title: Wireless Activation of Neurons in Brain Slices Using Nanostructured Semiconductor Photoelectrodes
Angewandte Chemie International Edition 2009, 48, No. 13, doi: 10.1002/anie.200806093
Clemens Burda | Angewandte Chemie
Further reports about: > Activation of neurons > Angewandte Chemie > Hippocampus > Semiconductor > electrical conduction > electrical power > electrochemical side reactions > micropipette > nerve cells > nerve impulses > neuronal circuits > photoelectrodes > semiconductor nanoparticles > semiconductor photoelectrodes > similar nerve impulses
Fingerprint' technique spots frog populations at risk from pollution
27.03.2017 | Lancaster University
Parallel computation provides deeper insight into brain function
27.03.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
27.03.2017 | Earth Sciences
27.03.2017 | Life Sciences
27.03.2017 | Life Sciences