Single neuronal recordings using surface micromachined polysilicon microelectrodes

Jit Muthuswamy, Murat Okandan, Nathan Jackson

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Bulk micromachining techniques of silicon have been used successfully in the past several years to microfabricate microelectrodes for monitoring single neurons in acute and chronic experiments. In this study we report for the first time a novel surface micromachining technique to microfabricate a very thin polysilicon microelectrode that can be used for monitoring single-unit activity in the central nervous system. The microelectrodes are 3 mm long and 50 μm × 3.75 μm in cross-section. Excellent signal to noise ratios in the order of 25-35 dB were obtained while recording neuronal action potentials. The microelectrodes successfully penetrated the brains after a microincision of the dura mater. Chronic implantation of the microprobe for upto 33 days produced only minor gliosis. Since the polysilicon shank acts as a conductor, additional processing steps involved in laying conductor lines on silicon substrates are avoided. Further, surface micromachining allows for fabricating extremely thin microelectrodes which could result in decreased inflammatory responses. We conclude that the polysilicon microelectrode reported here could be a complementary approach to bulk-micromachined silicon microelectrodes for chronic monitoring of single neurons in the central nervous system.

Original languageEnglish (US)
Pages (from-to)45-54
Number of pages10
JournalJournal of Neuroscience Methods
Issue number1
StatePublished - Mar 15 2005
Externally publishedYes


  • Action potentials
  • Brain implants
  • MEMS
  • Microprobes
  • Neural prosthesis
  • Single neurons
  • Surface micromachining

ASJC Scopus subject areas

  • Neuroscience(all)


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