title: Patterning human neuronal networks on photolithographically engineered silicon dioxide substrates functionalized with glial analogues.
abstract: Interfacing neurons with silicon semiconductors is a challenge being tackled through various bioengineering approaches. Such constructs inform our understanding of neuronal coding and learning and ultimately guide us toward creating intelligent neuroprostheses. A fundamental prerequisite is to dictate the spatial organization of neuronal cells. We sought to pattern neurons using photolithographically defined arrays of polymer parylene-C, activated with fetal calf serum. We used a purified human neuronal cell line [Lund human mesencephalic (LUHMES)] to establish whether neurons remain viable when isolated on-chip or whether they require a supporting cell substrate. When cultured in isolation, LUHMES neurons failed to pattern and did not show any morphological signs of differentiation. We therefore sought a cell type with which to prepattern parylene regions, hypothesizing that this cellular template would enable secondary neuronal adhesion and network formation. From a range of cell lines tested, human embryonal kidney (HEK) 293 cells patterned with highest accuracy. LUHMES neurons adhered to pre-established HEK 293 cell clusters and this coculture environment promoted morphological differentiation of neurons. Neurites extended between islands of adherent cell somata, creating an orthogonally arranged neuronal network. HEK 293 cells appear to fulfill a role analogous to glia, dictating cell adhesion, and generating an environment conducive to neuronal survival. We next replaced HEK 293 cells with slower growing glioma-derived precursors. These primary human cells patterned accurately on parylene and provided a similarly effective scaffold for neuronal adhesion. These findings advance the use of this microfabrication-compatible platform for neuronal patterning.
authors.affiliation: Centre for Integrative Physiology, School of Biomedical Sciences, The University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hughes
authors.forename: Paul M
authors.initials: PM
authors.lastname: Brennan
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Bunting
authors.forename: Katherine
authors.initials: K
authors.lastname: Cameron
authors.forename: Alan F
authors.initials: AF
authors.lastname: Murray
authors.forename: Mike J
authors.initials: MJ
authors.lastname: Shipston
mesh_terms: D041721:3T3-L1 Cells; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D018920:Coculture Techniques; D005909:Glioblastoma / Q000473:pathology; D057809:HEK293 Cells; D006801:Humans; D008027:Light; D051379:Mice; D009415:Nerve Net / Q000187:drug effects / Q000378:metabolism*; D058953:Neural Stem Cells / Q000187:drug effects / Q000473:pathology; D016501:Neurites / Q000187:drug effects / Q000378:metabolism; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism*; D011108:Polymers / Q000494:pharmacology; D051381:Rats; D012822:Silicon Dioxide / Q000494:pharmacology*; D023822:Tissue Engineering / Q000379:methods*; D014992:Xylenes / Q000494:pharmacology
chemical_list: D011108:Polymers; D014992:Xylenes; C011055:parylene; D012822:Silicon Dioxide
keywords: cell patterning; neuron; parylene; photolithography; silicon dioxide