CHARACTERIZATION OF PROBE INTERACTIONS WITH BRAIN TISSUE
Prof. Dr. Carola Haas (Contact PI)
Intracortical recording or stimulation for therapeutic purposes requires biocompatibility as well as long-term viability of neural probes. Factors, which are assumed to considerably influence stability of recording quality over time, are amongst others the formation of a glial scar and neurodegeneration, spatially restricted to the site of lesion. Therefore, understanding and comprehensively elucidating the host’s response, elicited upon implantation (1) the mechanical trauma of insertion, which severs capillaries, material of the extracellular matrix and cellular processes induce a high pressure zone around the implantation site (2) the sustained foreign body response, leading to neurodegeneration, formation of a glial scar as well as gradual remodeling of the environment, is essential for advancements in neurotechnology and the design of novel/better devices. In this context, CAPRI aimed at a systematic and long-term investigation of probe-tissue interactions using a variety of different and novel approaches: Polyimide-based flexible probes were implanted into the rat cortex and the host’s response was investigated at defined survival times following surgery. The methods employed included X-ray tomography (with subsequent 3D reconstruction), whole transcriptome analysis, electron microscopy, and immunohistochemistry. Applying these different techniques, we (1) could simultaneously reconstruct both neural probe and brain tissue at sub-micron resolution without the use of contrast agents by 3D tomographic imaging, (2) identify key molecules responsible for neuroinflammation at the implantation site by transcriptome analysis (3) quantify morphological changes in the vicinity of the implanted probe over time by confocal microscopy, and (4) construct new multichannel recording devices which may be immunologically invisible to the brain. We are sure that these results increase our understanding of probe-tissue interactions and will help to improve long-term recording- and stimulation stability.
Böhm T, Joseph K, Kirsch M, Moroni R, Hilger A, Osenberg M, Manke I, Johnston Midori, Stieglitz T, Hofmann UG, Haas CA, Thiele S. (2019). Quantitative synchrotron X‐ray tomography of the material‐tissue interface in rat brain cortex implanted with flexible neural probes. Sci Rep (in press).
Mottaghi S, Joseph K, Christ O, Feuerstein TJ, Hofmann UG. (2018). When the ostrich- algorithm fails: Blanking method affects spike train statistics. Front Neurosci 12: 293.
Haas CA: Brain Reorganisation under Pathological Conditions (invited talk), Gordon Research Conference "Neuroelectronic Interfaces", Galveston, Texas, USA, 2018.
Böhm T, Joseph K, Kirsch M, Moroni R, Hilger A, Manke I, Johnston M, Asplund M, Vomero M, Hofmann UG, Stieglitz T, Haas CA, Thiele S. X-ray tomographic 3D reconstruction of the brain-probe-interface in rat cortex. GRC “Neuroelectronic Interfaces”, Galveston, USA, 2018.
Kirsch M, Böhm T, Joseph K, Asplund A, Hofmann UG, Thiele S, Stieglitz T, Haas CA. Molecular and structural characterization of probe-tissue interactions in the rat brain. GRC “Neuroelectronic Interfaces”, Galveston, USA, 2018.
Johnston M, Böhm T, Joseph K, Asplund M, Hofmann UG, Thiele S, Haas CA. Semi- automated quantification of the CNS immune response at the probe-tissue-interface. Annual Meeting of the Neuroscience Society, San Diego, USA, 2018.
Stieglitz T, Vomero M, Joseph K, Johnston M, Ciarpella F, Kirsch M, Böhm T, Fadiga L, Thiele S, Haas CA, Hofmann UG, Asplund M. How flexibility and probe size influence chronic reliability: A study on batch processed polyimide-based intracortical neural arrays. Annual Meeting of the Neuroscience Society, San Diego, USA, 2018.
Johnston M, Böhm T, Joseph K, Asplund M, Follo M, Hofmann UG, Thiele S, Kirsch M, Haas CA. Molecular and structural characterization of probe-tissue interactions in the rat brain. 11th FENS Forum, Berlin, Germany, 2018.
Edited Book: Capadona JR, Hofmann UG (to be released 2019): “Bridging the Gap in Neuroelectronic Interfaces”, Front Neurosci (Special Research Topic: Neural Engineering).