title: Two cell circuits of oriented adult hippocampal neurons on self-assembled monolayers for use in the study of neuronal communication in a defined system.
abstract: In this study, we demonstrate the directed formation of small circuits of electrically active, synaptically connected neurons derived from the hippocampus of adult rats through the use of engineered chemically modified culture surfaces that orient the polarity of the neuronal processes. Although synaptogenesis, synaptic communication, synaptic plasticity, and brain disease pathophysiology can be studied using brain slice or dissociated embryonic neuronal culture systems, the complex elements found in neuronal synapses makes specific studies difficult in these random cultures. The study of synaptic transmission in mature adult neurons and factors affecting synaptic transmission are generally studied in organotypic cultures, in brain slices, or in vivo. However, engineered neuronal networks would allow these studies to be performed instead on simple functional neuronal circuits derived from adult brain tissue. Photolithographic patterned self-assembled monolayers (SAMs) were used to create the two-cell "bidirectional polarity" circuit patterns. This pattern consisted of a cell permissive SAM, N-1[3-(trimethoxysilyl)propyl] diethylenetriamine (DETA), and was composed of two 25 μm somal adhesion sites connected with 5 μm lines acting as surface cues for guided axonal and dendritic regeneration. Surrounding the DETA pattern was a background of a non-cell-permissive poly(ethylene glycol) (PEG) SAM. Adult hippocampal neurons were first cultured on coverslips coated with DETA monolayers and were later passaged onto the PEG-DETA bidirectional polarity patterns in serum-free medium. These neurons followed surface cues, attaching and regenerating only along the DETA substrate to form small engineered neuronal circuits. These circuits were stable for more than 21 days in vitro (DIV), during which synaptic connectivity was evaluated using basic electrophysiological methods.
authors.affiliation: Nanoscience Technology Center, University of Central Florida , 12424 United States Research Parkway, Suite 400, Orlando, Florida 32826, United States.
authors.forename: Darin
authors.initials: D
authors.lastname: Edwards
authors.forename: Maria
authors.initials: M
authors.lastname: Stancescu
authors.forename: Peter
authors.initials: P
authors.lastname: Molnar
authors.forename: James J
authors.initials: JJ
authors.lastname: Hickman
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D016764:Cell Polarity; D002478:Cells, Cultured; D006624:Hippocampus / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D055495:Neurogenesis / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D009435:Synaptic Transmission / Q000502:physiology*