title: Low-density neuronal networks cultured using patterned poly-l-lysine on microelectrode arrays.
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 (microCP). Polydimethysiloxane (PDMS) stamps were fabricated with relief structures resulting in patterns of 2 microm-wide lines for directing process growth and 20 microm-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/mm(2). 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.
authors.affiliation: Nano-Bioelectronics and Systems Research Center, Seoul, Republic of Korea. sangbum@helios.snu.ac.kr
authors.forename: Sang Beom
authors.initials: SB
authors.lastname: Jun
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hynd
authors.forename: Natalie
authors.initials: N
authors.lastname: Dowell-Mesfin
authors.forename: Karen L
authors.initials: KL
authors.lastname: Smith
authors.forename: James N
authors.initials: JN
authors.lastname: Turner
authors.forename: William
authors.initials: W
authors.lastname: Shain
authors.forename: Sung June
authors.initials: SJ
authors.lastname: Kim
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry*; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000502:physiology* / Q000648:ultrastructure; D008839:Microelectrodes; D008855:Microscopy, Electron, Scanning; D009415:Nerve Net / Q000502:physiology* / Q000648:ultrastructure; D009482:Neurophysiology / Q000295:instrumentation / Q000379:methods*; D009757:Nylons / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry*; D011188:Potassium / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D003470:Culture Media; D004129:Dimethylpolysiloxanes; D018691:Excitatory Amino Acid Antagonists; D009757:Nylons; D017470:Receptors, Glutamate; D016708:Synaptophysin; C085707:poly(dimethylsiloxane)-polyamide copolymer; D011107:Polylysine; D011188:Potassium