Combined in vivo recording of neural signals and iontophoretic injection of pathway tracers using a hollow silicon microelectrode

Z. Fekete, E. Pálfi, G. Márton, M. Handbauer, Zs Bérces, I. Ulbert, A. Pongrácz, L. Négyessy

Research output: Contribution to journalArticle

6 Citations (Scopus)


This paper presents the results of in vivo local release of a neuronal tracer, biotinylated dextran amine (BDA) in the rat somatosensory cortex using monolithically integrated microfluidic channel of a silicon neural microelectrode. The tracer injection is controlled by iontophoresis using Pt electrodes in the vicinity of the outlet of the microfluidic channel. Using 3–5 μA, 5–7 s on/off cycle and 15–20 min total injection time the localized injection resulted in clear anterograde and retrograde BDA labeling both within the cortex and in subcortical structures. Anterograde and retrograde labeling revealed the fine details of neuronal processes including dendritic spines and axon terminal-like endings. Injection sites appeared clear lacking any strong diffuse background labeling. Electrophysiological recording performed with the same microdevice immediately after the iontophoresis indicated normal cortical functioning. The results prove that the combination of in vivo multichannel neural recording and controlled tracer injection using a single implanted microdevice is feasible, and therefore it can be a powerful tool for studying the connectome of the brain.

Original languageEnglish
Pages (from-to)815-824
Number of pages10
JournalSensors and Actuators, B: Chemical
Publication statusPublished - Nov 29 2016



  • Biotinylated dextran amine
  • Microiontophoresis
  • Neural microelectrode
  • Neuroanatomical tracer injection
  • Neuronal labeling

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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