Patterned poly(chlorotrifluoroethylene) guides primary nerve cell adhesionand neurite outgrowth

Central nervous system (CNS) neurons, unlike those of the peripheral nervou s system, do not spontaneously regenerate following injury. Recently it has been shown that in the developing CNS, a combination of cell-adhesive and cell-repulsive cues guide growing axons to their targets. We hypothesized t hat by mimicking these guidance signals, we could guide nerve cell adhesion and neurite outgrowth in vitro. Our objective was to direct primary nerve cell adhesion and neurite outgrowth on poly(chlorotrifluoroethylene) (PCTFE ) surfaces by incorporating alternating patterns of cell-adhesive (peptide) and nonadhesive (polyethylene glycol; PEG) regions. PCTFE was surface-modi fied with lithium PEG-alkoxide, demonstrating the first report of metal-hal ogen exchange with an alkoxide and PCTFE. Titanium and then,gold were sputt ered onto PEG-modified films, using a shadow-masking technique that creates alternating patterns on the micrometer scale. PCTFE-Au regions then were m odified with one of two cysteine-terminated laminin-derived peptides, C-GYI GSR or C-SIKVAV. Hippocampal neuron cell-surface interactions on homogeneou sly modified surfaces showed that neuron adhesion was decreased significant ly on PEG-modified surfaces and was increased significantly on peptide-modi fied surfaces. Cell adhesion was greatest on CGYIGSR surfaces while neurite length was greatest on CSIKVAV surfaces and PLL/laminin positive controls, indicating the promise of peptides for enhanced cellular interactions. On patterned surfaces, hippocampal neurons adhered and extended neurites prefe rentially on peptide regions. By incorporating PEG and peptide molecules on the surface, we were able to simultaneously mimic cell-repulsive and cell- adhesive cues, respectively, and maintain the biopatterning of primary CNS neurons for over 1 week in culture. (C) 2000 John Wiley & Sons, Inc.