Abstract
Synaptic activity recorded from low-density networks of cultured rat hippocampal neurons was monitored using microelectrode arrays (MEAs). Neuronal networks were patterned with poly-l-lysine (PLL) using microcontact printing (μCP). Polydimethysiloxane (PDMS) stamps were fabricated with relief structures resulting in patterns of 2 μm-wide lines for directing process growth and 20 μm-diameter circles for cell soma attachment. These circles were aligned to electrode sites. Different densities of neurons were plated in order to assess the minimal neuron density required for development of an active network. Spontaneous activity was observed at 10-14 days in networks using neuron densities as low as 200 cells/mm2. Immunocytochemistry demonstrated the distribution of dendrites along the lines and the location of foci of the presynaptic protein, synaptophysin, on neuron somas and dendrites. Scanning electron microscopy demonstrated that single fluorescent tracks contained multiple processes. Evoked responses of selected portions of the networks were produced by stimulation of specific electrode sites. In addition, the neuronal excitability of the network was increased by the bath application of high K+ (10-12 mM). Application of DNQX, an AMPA antagonist, blocked all spontaneous activity, suggesting that the activity is excitatory and mediated through glutamate receptors.
Original language | English |
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Pages (from-to) | 317-326 |
Number of pages | 10 |
Journal | Journal of Neuroscience Methods |
Volume | 160 |
Issue number | 2 |
DOIs | |
State | Published - 15 Mar 2007 |
Bibliographical note
Funding Information:This work was supported by the International Collaboration Program, NBS-ERC (Nano Bioelectronics and Systems Engineering Research Center)/KOSEF (Korea Science and Engineering Foundation) and NIH, R01NS-044287, NSF, ECS-9876771. Authors also appreciate help from T.H. Lee and J.K. Lee for assistance in the fabrication of MEAs and stamp masters.
Keywords
- Microcontact printing
- Microelectrode arrays
- Neural networks
- Synapse formation