Low-cost silicon neural probe: fabrication, electrochemical characterization and in vivo validation


This paper presents the fabrication of a silicon neural probe using low-cost microfabrication technologies, such as thin-films deposition, blade dicing, and photolithography. The metal stack that forms the 9 microelectrodes of 50 × 50 µm2 area, the tracks and the pads were made of Ti and Pt, while the passivation stack was SiO2 and Si3N4. The fabricated probe was characterized using electrochemical impedance spectroscopy, before and after deposition of poly(3,4-ethylene-dioxythiophene) (PEDOT) on Pt microelectrodes. The electrochemical deposition of PEDOT, a conductive polymer, reduced the impedance of the Pt microelectrodes. The neural probe with PEDOT was used for in vivo electrophysiological acute recordings in an adult rat. The extracellular recordings were filtered to obtain the spike and local field potential (LFP) data, using Butterworth bandpass filters of 400–6000 Hz and 0.1–300 Hz, respectively. The results obtained with the fabricated neural probe validated its functionality, comparing with the signals acquired with a commercial neural probe, and the viability of the fabrication process, which avoids high–cost and complex etching processes.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10


  1. Bedard C, Destexhe A (2009) Macroscopic models of local field potentials and the apparent 1/f noise in brain activity. Biophys J 94:2589–2603. https://doi.org/10.1016/j.bpj.2008.12.3951

    Article  Google Scholar 

  2. Boretius T, Schuettler M, Stieglitz T (2011) On the stability of poly-ethylenedioxythiopene as coating material for active neural implants. Artif Organs 35:245–248. https://doi.org/10.1111/j.1525-1594.2011.01210.x

    Article  Google Scholar 

  3. Chung T, Wang JQ, Wang J et al (2015) Electrode modifications to lower electrode impedance and improve neural signal recording sensitivity. J Neural Eng. https://doi.org/10.1088/1741-2560/12/5/056018

    Article  Google Scholar 

  4. Fekete Z (2015) Recent advances in silicon-based neural microelectrodes and microsystems: a review. Sens Actuator B Chem 215:300–315. https://doi.org/10.1016/j.snb.2015.03.055

    Article  Google Scholar 

  5. Henrie JA, Shapley R (2005) LFP power spectra in V1 cortex: the graded effect of stimulus contrast. J Neurophysiol 94:479–490. https://doi.org/10.1152/jn.00919.2004

    Article  Google Scholar 

  6. Hong G, Lieber CM (2019) Novel electrode technologies for neural recordings. Nat Rev Neurosci 20:330–345. https://doi.org/10.1038/s41583-019-0140-6

    Article  Google Scholar 

  7. Kandel ER, Schwartz JH, Jessell TM et al (2012) Principles of neural science, 5th edn. McGraw-Hill, New York

    Google Scholar 

  8. Kim GH, Kim K, Lee E et al (2018) Recent progress on microelectrodes in neural interfaces. Materials 11:1–25. https://doi.org/10.3390/ma11101995

    Article  Google Scholar 

  9. Lewandowska MK, Bakkum DJ, Rompani SB, Hierlemann A (2015) Recording large extracellular spikes in microchannels along many axonal sites from individual neurons. PLoS ONE 10:1–24. https://doi.org/10.1371/journal.pone.0118514

    Article  Google Scholar 

  10. Ludwig KA, Langhals NB, Joseph MD et al (2011) PEDOT polymer coatings facilitate smaller neural recording electrodes. J Neural Eng. https://doi.org/10.1088/1741-2560/8/1/014001

    Article  Google Scholar 

  11. Márton G, Bakos I, Fekete Z et al (2014) Durability of high surface area platinum deposits on microelectrode arrays for acute neural recordings. J Mater Sci Mater Med 25:931–940. https://doi.org/10.1007/s10856-013-5114-z

    Article  Google Scholar 

  12. Oliveira JF, Dias NS, Correia M et al (2013) Chronic stress disrupts neural coherence between cortico-limbic structures. Front Neural Circuits 7:1–12. https://doi.org/10.3389/fncir.2013.00010

    Article  Google Scholar 

  13. Paxinos G, Watson C (2013) The rat brain in stereotaxic coordinates, 7th edn. Elsevier, Amsterdam

    Google Scholar 

  14. Seymour JP, Wu F, Wise KD, Yoon E (2017) State-of-the-art MEMS and microsystem tools for brain research. Microsyst Nanoeng 3:1–16. https://doi.org/10.1038/micronano.2016.66

    Article  Google Scholar 

  15. Zhang S, Zeng X, Matthew D et al (2016) Selection of micro-fabrication techniques on stainless steel sheet for skin friction. Friction 4:89–104. https://doi.org/10.1007/s40544-016-0115-9

    Article  Google Scholar 

  16. Zhang Y-F, Reynolds JNJ, Cragg SJ (2018) Pauses in cholinergic interneuron activity are driven by excitatory input and delayed rectification, with dopamine modulation. Neuron 98:918–925. https://doi.org/10.1016/j.neuron.2018.04.027

    Article  Google Scholar 

  17. Zhao L, He Y (2013) Power spectrum estimation of the Welch method based on imagery EEG. Appl Mech Mater 278–280:1260–1264. https://doi.org/10.4028/www.scientific.net/AMM.278-280.1260

    Article  Google Scholar 

Download references


ANI supports this work through the Brain-Lighting project by FEDER funds through Portugal 2020, COMPETE 2020 with the reference POCI-01-0247-FEDER-003416. This work is also supported by FCT with CMEMS-UMinho Strategic Project, reference UIDB/04436/2020, the project Infrastructures Micro&NanoFabs@PT, reference NORTE-01-0145-FEDER-022090, POR Norte, Portugal 2020 and by the project OpticalBrain, reference PTDC/CTM-REF/28406/2017, by FEDER funds through the COMPETE 2020 - Programa Operacional Competitividade e Internacionalização (POCI). The authors acknowledge also FCT CEECIND grants, Bial Foundation Grants 207/14 and 037/18 to JO; Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000013); FEDER Funds, through the Competitiveness Factors Operational Programme (COMPETE), and The National Fund, through the FCT (POCI-01-0145-FEDER-007038). The authors also thank to N. A. P. de Vasconcelos from ICVS-University of Minho for the implementation of the setup for the in vivo recordings.


No funding to declare

Author information




The work presented in this paper was a collaboration of all authors. J. A. Rodrigues, S. Pimenta, J. F. Ribeiro, and J. H. Correia conceived and designed the experiments. The fabrication process was performed by S. Pimenta, J. P. Pereira, N. M. Gomes, M. R. Souto, H. C. Fernandes and J. F. Ribeiro. The electrochemical impedance spectroscopy characterization and PEDOT deposition was performed by J. A. Rodrigues. J. A. Rodrigues, S. Pimenta, I. Caetano, C. Soares-Cunha and J. F. Oliveira performed the in vivo electrophysiological acute recordings. J. A. Rodrigues and S. Pimenta analyzed the data. The first draft of the manuscript was written by J. A. Rodrigues and S. Pimenta, and all authors commented on previous versions of the manuscript. J.H.C supervised all the work.

Corresponding author

Correspondence to José A. Rodrigues.

Ethics declarations

Conflicts of interest

The authors declare that they have no conflict of interest.

Ethics approval

All procedures performed in studies involving animals were in accordance with the European Regulations (European Union Directive 2010/63/EU). Animal facilities and the people involved in animal procedures were certified by the Portuguese regulatory entity – DGAV (Direção-Geral de Alimentação e Veterinária). All protocols followed the guidelines of Life and Health Sciences Research Institute, the Institutional Animal Care and Use Committee from University of Minho and were approved by the Ethics Committee of the Life and Health Sciences Research Institute.

Consent to participate

Not applicable.

Consent for publication

Not applicable.

Availability of data and material

Not applicable.

Code availability

Not applicable.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Rodrigues, J.A., Pimenta, S., Pereira, J.P. et al. Low-cost silicon neural probe: fabrication, electrochemical characterization and in vivo validation. Microsyst Technol 27, 37–46 (2021). https://doi.org/10.1007/s00542-020-04898-3

Download citation