An approach for creating polymeric microstructures with various aspect ratios for cellular analysis applications

This paper reports a flexible fabrication process to manufacture polymeric microstructures with various aspect ratios using a micro molding process. In this study, a silicon template with deep holes (2 mu m in diameter) was fabricated and a two-phase vacuum pressure-assisted process was conducted. The liquid polymer contacting with the template was raised into the deep holes due to the differential pressure between the trapped air in the holes and the ambient pressure. The microstructures were solidified by thermal curing at an elevated temperature (65 degrees C). The height of the resulting polymeric microstructures, ranging from submicron to more than 10 mu m, was controlled by tuning the operation parameters in the micro molding process. A proof-of-principle experiment was carried out in isolated cardiac myocytes to measure the cellular forces towards the polymeric microstructures. Moreover, simultaneous cell alignment and force measurement was demonstrated using an advanced structure fabricated using such a technique. This approach reported here differs from the existing ones in that it enables the "1-to-n" replication, thereby lowering the fabrication cost and complexity. This study has a potential application in a variety of polymer-based micro total analysis systems, especially where the polymer microstructures serve as mechanical sensors. (c) 2005 Elsevier B.V. All rights reserved.