Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Schmidt, T.
Optical Control of Neuronal Signaling with Organic Bioelectronics
PhD-Studium (Doctor of Philosophy); Humanmedizin; [ Dissertation ] Medizinische Universität Graz; 2022. pp. 131
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Patz Silke
- Schindl Rainer
- Schreibmayer Wolfgang
- Altmetrics:
- Abstract:
- Neurological disorders or injuries after traumatic events often destroy the natural function of neurons to process or transduce information. The artificial connection between technology and the living organism can treat, monitor, or restore such functions and conditions. All bioelectronic devices must address two main challenges: biocompatibility and power supply. In this work, I introduce two novel approaches based on light-sensitive organic pigments that require no wiring or genetic modification to control cell stimulation and that are safe in terms of use with living cells. In this thesis, I have investigated the interaction of neuronal cell membranes with colloidal macrocrystals made from Epindolidione pigments that feature a 3D-shaped microstructure on their surface. Neurons developed extensive networks and stable interactions with these structures. Neurites that grew toward the organic pigments attached to them and remodeled connections during cell maturation. Photothermocapacitive stimulation of neuron-pigment complexes with laser light depolarized the cell membrane but was unable to induce action potential firing. I also benchmarked the performance of Organic Electrolytic Photocapacitors (OEPCs) on photocapacitive stimulation of mammalian cells with visible red light that can penetrate through the skin into tissues. OEPCs form a planar photovoltaic device with the n- and p-type semiconducting pigments N,N’-dimethyl perylene tetracarboxylicdiimide (PTCDI) and metal free phthalocyanine (H2Pc). Electrophysiology recordings of human embryonic kidney (HEK) cells transfected with the voltage-gated potassium channel Kv1.3 showed a time-dependent channel activation and a channel conductance shift of around 30 mV when placed on OEPCs. Neurons stimulated with millisecond pulses fired reliably action potentials on single and repetitive light pulses. The findings demonstrate that organic pigment-based bioelectronics are safe to use in vitro and enable a nongenetic manipulation of neuronal signaling with light and high precision for future in vivo applications.