MICROMETER RESOLUTION SILANE-BASED PATTERNING OF HIPPOCAMPAL-NEURONS - CRITICAL VARIABLES IN PHOTORESIST AND LASER-ABLATION PROCESSES FOR SUBSTRATE FABRICATION

Toward the goal of creating patterns of primary hippocampal neurons in low density culture, we investigated techniques to fabricate micromin iature grids of organofunctional silanes on glassy surfaces, A new pho toresist (PR) process, Selective Silane Removal (SSR), was developed a nd compared to two previously developed techniques which use PR and la ser patterning, The grid patterns consisted of 27 combinations of path width, length, and intersection (node diameter), The background consi sted of squares bounded by the paths, The best neuron patterning was o bserved on substrates produced by the SSR process where cytophilic ami nosilane is uniformly deposited and selectively removed from the backg round, Controlling water during aminosilane deposition was critical to good neuronal growth and patterning, Oxygen plasma etching of backgro und regions prior to cytophobic phenylsilane binding significantly red uced off-pattern cell growth, Up to 90% of somata grown on these subst rates complied to the pattern, and an average of 77% of background reg ions were free of neurites or cells connected to the pattern, The high est laser energy density, 120 mJ/cm(2), produced the best compliance o n lased substrates, with an average of 35% of background regions free of connected cells and neurites, but considerable variation across the surface, On substrates with excellent patterning, compliance to nodes was found to be dependent on pattern dimensions, with 20-mu m node di ameters and 80-mu m internodal path lengths increasing compliance.