High Aspect Ratio SU-8 Structures for 3-D Culturing of Neurons

This paper presents a simplified fabrication method for high aspect ratio micromachined towers for culturing 3-D networks of neurons. The photosensitive epoxy SU-8 was used as both the tower material and the substrate. This material was particularly suitable because of its mechanical stability, biocompatibility, and potential for high aspect ratio fabrication. Fabrication is effectively simplified by a double exposure technique, allowing tower structures and an integral SU-8 substrate to be formed from the same epoxy deposition, thereby addressing column-to-substrate adhesion issues that have traditionally limited the aspect ratios achieved with conventional fabrication techniques. Aspect ratios up to 35:1 have been achieved, and successful cell culturing has been demonstrated.