Developmental neurobiology implications from fabrication and analysis of hippocampal neuronal networks on patterned silane-modified surfaces

We have determined the parameters necessary to fabricate reproducible neuro nal patterns which we are using to begin studying fundamental issues in dev elopmental neurobiology. The addition of a beam homogenizer, as well as a n ew surface preparation, has enabled the routine production of reproducible, high-resolution (2-20 mu m) organosilane patterns. The effects of surface preparation and beam dosage were monitored using X-ray photoelectron spectr oscopy (XPS) and proof of patterning is provided by high-resolution imaging XPS. We also report the guidance of neuronal adhesion and neurite outgrowt h and the creation of reproducibly defined circuits of embryonic (E18-19) r at hippocampal neurons using these patterned surfaces in vitro. We have ach ieved a >50% rate of pattern formation, and at times the rate approaches 90 %. We are using these patterns to address the issue of how geometric patter n cues might be used to affect cell-to-cell communication and we report the preliminary results on the synaptic development of the hippocampal neurons using dual patch-clamp electrophysiology. We monitored neurite outgrowth a nd the emergence of both spontaneous and evoked synaptic activity for both patterned and unpatterned (control) hippocampal cultures. The results indic ate the intriguing possibility that geometry itself may be a modulating or trophic factor for cell development.