EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Motor neuron diseases like Parkinson’s can induce severe tremors in later stages, which seriously impair the daily life of elderly patients, particularly when drug-based treatments have ceased to work. A possible way to improve the patients’ quality of life is deep brain stimulation (DBS) treatments. Here, platinum neural electrodes are implanted into the brain, providing electric pulses to stimulate the subthalamic nucleus (STN) and in turn tune neuronal activity. Even though this treatment is routinely applied in clinical practice, difficulties such as low stimulation efficiency and reduced battery capacity of the pulse generator due to the increase of impedance over time between electrode tip and brain tissue occur.

Here we show that the impedance of neural electrodes can be significantly reduced in case their surface area is increased by sub-monolayer deposition of ligand-free laser-fabricated platinum nanoparticles (PtNPs). The coating of 3D electrode surfaces is done using electrophoretic deposition (EPD) in a custom-designed chamber with a field strength of 5 V/cm and a platinum mass concentration of 100 µg/ml. We compared the impact of DC (5 min) and pulsed-DC EPD (period of 1 µs and a duty cycle of 50%, 10 min) on stimulation conditions. Our findings reveal that the pulsed-DC coating procedure yields a more homogeneous surface coating and also the impedance is significantly reduced in contrast to the uncoated controls, an effect which could not be observed for DC-EPD in our previous works. In consecutive studies, the coated electrodes will undergo long term in vitro stimulations in saline solutions and in vivo stimulations in rat models and the influence of DC and pulsed DC electric fields on their functionality will be evaluated.