Neural Engineering Seminar
In person in Wickenden 321 and via Zoom:
Meeting ID: 928 0482 8495 Passcode: 185518
Presenter:
Ulrich G. Hofmann <ulrich.hofmann@coregen.uni-freiburg.de
Friberg Institute for Advanced Studies, Freiberg, Germany
"I will present the state of this work in progress and the current limitations in local heating brought upon us by commercial nanoparticles".
In all of the brain-machine interfacing industry there is high hopes to have found the least detrimental implant type in flexible, metal or polymer based multisite-probes. Apparent proof is given by immunohistochemical micrographs reporting no abnormality. Unfortunately, this may be based on a Streetlight Fallacy () utilizing less than optimal scientific tools for an assessment. When introducing more recent molecular biology tools like transcriptomic analysis even flexible probes disappoint with respect to their benevolence on brain tissue [1]. A strong state of neuroinflammation is caused by these implants which doesn’t wear off over time and is even marked by oncogen activation. Very much to our surprise, part of this neuroinflammation can already be caused by the very procedure needed to insert probes into brain: The craniotomy itself! („Open up the brain and it will never look the same!“ neurosurgeons tend to say…)
Motivated by this, we try to pave new ways to avoid implanting macroscopic probes through the skull yet still maintaining deep brain stimulation benefits. To this end we learned to open the Blood-Brain-Barrier locally by mild hyperthermia at arbitrary locations throughout the brain [2] which would then allow to deploy nanoparticle actuators to any chosen spot. Locations throughout the brain are addressed contactless by the Field-Free Spot of a Magnetic Particle Imaging (MPI) device equipped with an additional Alternating Magnetic Field (AMF) heating coil - a truly Theranostic Device [3].
[1] Joseph, K., M. Kirsch, et al. (2021). "Transcriptional characterization of the glial response due to chronic neural implantation of flexible microprobes." Biomaterials 279: 121230DOI: 10.1016/j.biomaterials.2021.121230
[2] Bär, S., O. Buchholz, et al. (2023). "Thermal threshold for localized Blood-Brain-Barrier disruption." arXiv-DOI: 10.48550/arXiv.2306.09214.
[3] Buchholz, O., K. Sajjamark, et al. (2023). "In situ theranostic platform uniting highly localized magnetic fluid hyperthermia, magnetic particle imaging, and thermometry in 3D." in press with Theranostics ; arXiv -DOI: 10.48550/arXiv.2304.06554.