Soft mold-dry etch: a novel hydrogel patterning technique for biomedical applications

Ming Lei; Yuandong Gu; Antonio Baldi; Ronald Siegel; Babak Ziaie

doi:10.1109/IEMBS.2004.1403585

Soft mold-dry etch: a novel hydrogel patterning technique for biomedical applications

Conf Proc IEEE Eng Med Biol Soc. 2004:2004:1983-6. doi: 10.1109/IEMBS.2004.1403585.

Authors

Ming Lei¹, Yuandong Gu, Antonio Baldi, Ronald Siegel, Babak Ziaie

Affiliation

¹ Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA.

PMID: 17272105
DOI: 10.1109/IEMBS.2004.1403585

Abstract

This paper introduces a novel patterning technique for environmentally sensitive hydrogels using a combination of soft mold and dry etch. This method alleviates the need for photoinitiators used in conventional approaches and is applicable to a broad range of hydrogels. This technique is also compatible with the traditional microfabrication methods thus allowing the integration of hydrogels with microelectronics and MEMS microstructures. Hydrogels of different shapes and sizes were patterned in a batch scale (wafer-level) with resolutions of up to 2.5 microm. The patterned pH-sensitive hydrogels with micron-sized dimensions were able to respond within seconds. Deposited aluminum thin films on top of hydrogel microstructures was used to fabricate environmentally sensitive free standing micro-mirrors with a vertical displacement sensitivity of 7 microm/pH at pH 5.0. These structures open the possibility of fabricating on-chip photonic-based hydrogel microsensors.