Scalloped electrodes for highly sensitive electrical measurements

In this work we introduce a novel out-of-plane electrode with pronounced scalloped surface and high aspect ratio for electrical recordings of brain tissue in vitro, with the aim to reduce significantly the impedance of the measuring system. The profile and height of the structures is tailored by means of silicon fabrication techniques that sharpen them progressively and in a controlled manner. We will show that the use of the scalloped area achieves a great decrease in impedance, which is very significant for a reduction of noise in electrical measurements. The measured impedance reflects an important improvement in comparison with already available systems. Additionally, first test of durability prove the robustness of these needle-like electrodes during indentation motions. In conclusion, the resulting electrodes are robust, sharp structures that decrease the typical impedance of microelectrodes and are potentially suited for indentation and recording of brain tissue.