07-Apr-2017 - Albert-Ludwigs-Universität Freiburg

No sugar coating, but sweet nonetheless

First long-term stabile brain implant developed based on an anti-inflammatory coating

Complex neurotechnological devices are required to directly select and influence brain waves inside the skull’s interior. Although it has become relatively easy to implement the devices, researchers are still faced with challenges when trying to keep them running properly in living organisms over time. But that could be changing now, thanks to a new method from Freiburg. A research team was able to create a microprobe that grows into the neural tissue without inflammation and with the help of a medicinal coating. Even after twelve weeks it is still able to deliver strong signals. Now that such implants are no longer required to be replaced as often, they are able to open the doors for better diagnoses while making life easier for the chronically ill – such as Parkinson’s patients that need to be treated with brain stimulation methods. The study has appeared in the journal „Biomaterials“ and is based on the group’s earlier research on conductive and absorbent plastics.

The microsystems engineer Christian Böhler from Dr. Maria Asplund’s junior research group in the Cluster of Excellence BrainLinks-BrainTools, Prof. Dr. Thomas Stieglitz, chair for biomedical microtechnology at the Institute for Microsystem Technology and Prof. Dr. Ulrich G. Hofmann, the section for neuroelectronic systems in the Department of Neurology at the University Hospital Freiburg have participated in the research. „After a while, the immune system tends to treat most of the bidirectional neural implants – that is, those that are implanted for measuring and stimulating simultaneously – as a foreign object. That is the reason their functionality becomes so limited. After a few weeks they barely give off any signals at all,“ says Böhler. The junior research group has shown that flexible microprobes made of so-called polyimides offer distinct advantages over implants made of silicon, for instance. „At the same time, inflammatory reactions can arise that make the electrodes unserviceable or that ultimately lead to the implant’s removal,“ adds Asplund. In their study, the researchers show that, based on an animal model, these side effects can be delayed longer by using a special coating on the electrodes placed on the polyimide implant.

The electrodes’ coating is made from the polymer PEDOT that absorbs medicine and, when applying negative voltage, releases it again – in this case, the anti-inflammatory compound dexamethasone. „In this way, we can pour the medicine directly around the implant, regulate the dosage and determine the time it is administered,“ explains Böhler. Compared to traditional methods for drug administering, a much lower dosage can be used. It also makes it possible to limit the effects to a specific area. In that way, undesirable side effects from the medicine can be reduced. As early as the beginning of 2016 the team showed that PEDOT has ideal characteristics as a drug carrier.

„We are able to reinforce the flexible microprobes’ superior nature over other designs with our study,“ Asplund summarizes. The implant from the Freiburg microsystems technology even holds together longer: „We are on the cusp of a breakthrough in a new generation of neuronal interfaces. We can finally build microprobes with a longer shelf life through our coating method.“ Of that Böhler is certain. Many more promising avenues for long-term treatments with, for instance, deep brain stimulation can be explored with this system. Patients whose nervous system requires not only regular stimulation but also close measurements and monitoring, such as those with Parkinson’s or epilepsy as well as people with obsessive-compulsive disorders or severe depression.

Facts, background information, dossiers

  • side effects
  • microtechnology
  • implants
  • dexamethasone
  • Universität Freiburg
  • polyimides
  • deep brain stimulation
  • sugars
  • biomaterials
  • drug delivery

More about Uni Freiburg

  • News

    Molecular structure of one of the most important receptors in the immune system unraveled

    The surface of B cells is covered with antigen receptors with which they recognize invading pathogens such as bacteria and viruses. When a B cell receptor binds to an antigen, that is, to a foreign structure, the B cell is activated and triggers the production of antibodies. Antibodies are ... more

    A molecular machine at work

    The greenhouse gas nitrous oxide (N2O) is produced as a by-product of industrial processes and through the use of fertilizers in agriculture. It is making a steadily growing contribution to climate change and the depletion of the ozone layer. It is so chemically unreactive that it remains i ... more

    New discoveries about the origin of the brain’s immune system

    What gets into the brain and what doesn’t is strictly regulated. Researchers at the Faculty of Medicine at the University of Freiburg have now studied phagocytes that coat the blood vessels in the brain and reinforce the blood-brain barrier. As the scientists from the Institute of Neuropath ... more

  • q&more articles

    Modular biofactories at the cellular level

    Despite his love for complex molecular architectures, this „dyed-in-the-wool“ bio-organic chemist has never embraced the conventional segregation of synthetic polymers and bio­logical macromolecules. All molecules are composed of atoms, after all. Why make an artificial distinction? Why not ... more

    Bookmarks

    From a pluripotent stem cell a muscle cell or a liver cell can form, which despite their difference in appearance, are genetically identical. From one and the same genotype, therefore, the most diverse phenotypes can be formed – epigenetics is making it possible! It is a very exciting area ... more

  • Authors

    Dr. Stefan Schiller

    Stefan M. Schiller studied chemistry at Gießen (Mainz, Germany) and the University of Massachusetts, majoring in macromolecular chemistry and biochemistry. For his doctorate in biomimetic membrane systems he worked till 2003 at the Max Planck Institute for Polymer Research in Mainz. Researc ... more

    Julia M. Wagner

    Julia M. Wagner studied pharmacy in Freiburg (licensure 2008). Since 2008 she is a PhD student and research assistant in the group of Professor Dr. M. Jung. Her research focuses ­on the cellular effects of histone deacetylase inhibitors. more

    Prof. Dr. Manfred Jung

    Manfred Jung is a graduate of the University of Marburg, where he studied pharmacy (licensure  1990) and obtained his doctorate in pharmaceutical chemistry with Prof. Dr. W. Hanefeld. After a post-doctorate at the University of Ottawa, Canada, he began with independent research in 1994 ­at ... more

q&more – the networking platform for quality excellence in lab and process

The q&more concept is to increase the visibility of recent research and innovative solutions, and support the exchange of knowledge. In the broad spectrum of subjects covered, the focus is on achieving maximum quality in highly innovative sectors. As a modern knowledge platform, q&more offers market participants one-of-a-kind networking opportunities. Cutting-edge research is presented by authors of international repute. Attractively presented in a high-quality context, and published in German and English, the original articles introduce new concepts and highlight unconventional solution strategies.

> more about q&more

q&more is supported by: