Development of an electrochemical characterization setup for stimulation electrodes

Introduction

Electrodes are the key component to reliably interface electronics with nervous tissue in neuroprosthetic applications. They can be used bidirectionally, i.e. for recording and eliciting neural activity. In general, the electrodes' electrochemical properties determine its functionality. In particular in stimulation, a low impedance and the ability to pass as much charge as possible without driving the electrode potential out of  the so-called water window are crucial [1], [2]. Outside of this potential window, hydrolysis of water can lead to irreversible damage to the surrounding tissue. To ensure long-term stability of the electrodes after implantation and during chronic stimulation, electrochemical tests need to be performed beforehand. In this project, our aim is to build an experimental setup which can be used for testing our neural stimulation electrodes [3].

Aim & research methods

In this project, we want to develop a setup that can apply biphasic stimulation pulses on an electrode in a three-electrode setup and measure the electrode polarization versus the reference electrode. The setup should have a connection to a host from which all relevant parameters can be set and measurement data can be read through a graphical user interface. The project will thus include:

  1. Design of the stimulation and acquisition electronics and their implementation.
  2. Programming of the microcontroller on the board to control all actuation, data acquisition and data transfer.
  3. Writing a graphical user interface.

You will be introduced in an interdisciplinary working environment and will learn the following techniques:

  1. How an entire experimental testing system is built.
  2. Analog and digital electronic circuit design.
  3. Embedded programming.
  4. Electrochemical characterization techniques for electrodes.

Requirements

  1. Dedication and motivation to work on an interdisciplinary research topic.
  2. Experience in electronics design.
  3. Experience with PCB design software (Altium Designer, Eagle, KiCad or equivalent).
  4. Experience in programming microcontrollers (ARM Cortex-M).

Possible starting date & further information

Potential starting date is as soon as possible. For further details and application contact Korkut Terkan in person or via email.

References

  1. S. F. Cogan, „Neural Stimulation and Recording Electrodes“, Annu. Rev. Biomed. Eng., Bd. 10, Nr. 1, S. 275–309, 2008.
  2. C. Boehler, F. Oberueber, T. Stieglitz, und M. Asplund, „Nanostructured platinum as an electrochemically and mechanically stable electrode coating“, in 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Seogwipo, 2017, S. 1058–1061.
  3. T. Dobbelaere, P. M. Vereecken, und C. Detavernier, „A USB-controlled potentiostat/galvanostat for thin-film battery characterization“, HardwareX, Bd. 2, S. 34–49, Okt. 2017.