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
New mechanisms uncovered explaining frost tolerance in plants
26.09.2016 | Technische Universität München
Chains of nanogold – forged with atomic precision
23.09.2016 | Suomen Akatemia (Academy of Finland)
The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.
“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...
With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.
Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...
For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.
Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...
At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.
In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...
Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.
K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...
23.09.2016 | Event News
20.09.2016 | Event News
16.09.2016 | Event News
26.09.2016 | Materials Sciences
26.09.2016 | Materials Sciences
26.09.2016 | Materials Sciences