Development of a robotic dispensing system to fabricate soft neural interfaces

Introduction

Soft and conformal electrodes used for neural interfacing in the central or peripheral nervous system offer a promising route towards neuroprosthetic devices to restore lost motor and sensor functions inside the body [1, 2]. While the fabrication of these devices relies mainly on standard lithographic micromanufacturing methods [3], printing approaches are being developed to enable fast prototyping and generate three dimensional structures without the need for clean-room facilities [4–6]. Our aim is to develop a robotic dispensing system which will enable us to print electrical insulation layers out of silicone and electrical conductors out of novel composites made from conducting polymers and carbon-based materials.

Aim & research methods

In this project we want to attach a self-designed syringe and needle holder to a 3D cartesian robot (GIX Microplotter II from Sonoplot) to serve as the dispensing system. Afterwards we want to print various geometries of electrode arrays and characterize them electrochemically.

  1. Optimize or directly use a self-designed syringe and needle holder which will be the print head.
  2. Write a script (in any language you want, preferred in Python) to control the three axes of the robot and synchronize the axis movement to the pressure control unit (Elveflow) which is used to extrude the liquid (insulator, conductor) from the syringe.
  3. Print initial test structures with a silicone ink (PDMS, Sylgard 184).
  4. Prepare a conducting composite material with PEDOT:PSS and carbon nanotubes and print initial test structures with it.
  5. Characterize the printed structures using electrochemical techniques.

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

  1. Mechatronic system development.
  2. Innovative fabrication methods of microsystems and novel materials for the use of neural electrodes.
  3. Electrochemical characterization methods (cyclic voltammetry, impedance spectroscopy, …).
  4. Cell-chip coupling.

Requirements

  1. Dedication and motivation to work on an interdisciplinary research topic.
  2. Excellent analytical and experimental skills.
  3. Experience with CAD programs.
  4. Programming experience with APIs.

Possible starting date & further information

Potential starting date is as soon as possible (please note the current shutdown of TUM's facilities until April 19th, as of April 2nd). Explorative or preparatory work in this context can also be given out as an internship. For further details and application contact Korkut Terkan.

References

  1. I. R. Minev et al., „Electronic dura mater for long-term multimodal neural interfaces“, Science, Bd. 347, Nr. 6218, S. 159–163, Jan. 2015, doi: 10.1126/science.1260318.
  2. N. Vachicouras et al., „Microstructured thin-film electrode technology enables proof of concept of scalable, soft auditory brainstem implants“, Sci. Transl. Med., Bd. 11, Nr. 514, S. eaax9487, Okt. 2019, doi: 10.1126/scitranslmed.aax9487.
  3. S. P. Lacour et al., „Flexible and stretchable micro-electrodes for in vitro and in vivo neural interfaces“, Med. Biol. Eng. Comput., Bd. 48, Nr. 10, S. 945–954, Okt. 2010, doi: 10.1007/s11517-010-0644-8.
  4. H. Yuk et al., „3D printing of conducting polymers“, Nat. Commun., Bd. 11, Nr. 1, S. 1604, Dez. 2020, doi: 10.1038/s41467-020-15316-7.
  5. Y. Tong et al., „A Hybrid 3D Printing and Robotic-assisted Embedding Approach for Design and Fabrication of Nerve Cuffs with Integrated Locking Mechanisms“, MRS Adv., Bd. 3, Nr. 40, S. 2365–2372, 2018, doi: 10.1557/adv.2018.378.
  6. M. Athanasiadis, A. Pak, D. Afanasenkau, and I. R. Minev, „Direct Writing of Elastic Fibers with Optical, Electrical, and Microfluidic Functionality“, Adv. Mater. Technol., S. 1800659, März 2019, doi: 10.1002/admt.201800659.