Interfacing SH-SY5Y human neuroblastoma cells with SU-8 microstructures

Microwell structures were fabricated using SU-8 photoresist for engineering a quasi-three-dimensional (quasi-3D) microenvironment for cultured neuronal cells. SH-SY5Y human neuroblastoma cells were successfully integrated into microwells of a nominal diameter of 100 μm, with or without 10-μm wide microchannels connecting neighboring microwells, in an aspect ratio (ratio of structure depth over width) of approximately 1. With the help of polyethylene glycol stamping and laminin coating, a neuronal-like network was achieved by integrating populations of SH-SY5Y cells with a microwell network pattern. Resting membrane potential establishment was evaluated with confocal microscopy and the potentiometric fluorescent dye tetramethylrhodamine methyl ester. It was found that the intra/extracellular fluorescent intensity ratio (R) was 2.4 ± 1.4 [n (number of cells measured) = 112] for SH-SY5Y cells on flat SU-8 substrates on day 5 into differentiation, which was not significantly different from the ratio on day 13 into differentiation, 2.0 ± 1.8 (n = 104) (P > 0.05). For cells in the microwell network structures, R was 4.8 ± 4.7 (n = 51) and 3.9 ± 3.2 (n = 62) on days 5 and 13 into differentiation, respectively (P > 0.5). Cells within the network structures had higher R ratios than on flat substrates, for either day 5 or 13 into differentiation (P < 0.01). These results demonstrated that the well network structures, or topographically patterned substrates, were more suitable formats for promoting SH-SY5Y cell resting membrane potential establishment than flat substrates, suggesting the potential to control cellular function through substrate topography engineering.