Hydrogel-Based Micromachined Platforms for Physiological Sensing and Smart Flow Control

Professor Babak Ziaie, School of Electrical and Computer Engineering, Purdue University

ABSTRACT: Integration of environmentally sensitive hydrogels with micromachined components has proven to be a powerful tool in creating smart components (sensors and actuators) for microsystems operating in aqueous media such as body fluids. Hydrogels are three-dimensional crosslinked polymer networks capable of undergoing reversible volume change in response to different stimuli (temperature, pH, glucose concentration, etc). This volume change depends on water absorption-expulsion kinetics resulting in response times of up to several hours for mm-sized hydrogels. Reducing their dimensions to the _m-range and integrating them with MEMS microstructures can shorten their response time (to seconds) making them attractive for many microsystem applications (e.g., microfluidics, lab on a chip, and _TAS). In this seminar, I will discuss several MEMS-based hydrogel-actuated microdevices developed in my laboratory. These include: 1) a hydrogel-actuated microvalve with a porous back-plate, 2) a hydrogel-gated smart flow controller, 3) a wireless microtransponder for subcutaneous glucose measurement, and 4) an ultrasensitive chemical sensor based on a self-aligned dry-patterned environmentally sensitive hydrogel.
BIO: Babak Ziaie received his doctoral degree in Electrical Engineering from the University of Michigan in 1994. His dissertation was related to the design and development of an implantable single channel microstimulator for functional neuromuscular stimulation. From 1995-1999 he was a postdoctoral-fellow and an assistant research scientist at the Center for Integrated Microsystems (CIMS) of the University of Michigan. He subsequently joined the Electrical and Computer Engineering Department of the University of Minnesota as an assistant professor (1999-2004). Since Jan 2005, he has been with the School of Electrical and Computer Engineering at Purdue University where he is an associate professor. His research interests are mostly related to biomedical applications of MEMS and microsystems. These include implantable wireless microsystems for diagnosis and management of glaucoma, hydrogel-based microsystems for physiological sensing and active flow control, multi-channel wideband wireless interfaces for central nervous system (brain/machine interface), biomimetic sensors and actuators, and ultra-sensitive sensors for biological (molecular and cellular) applications. Dr. Ziaie is the recipient of the NSF Career award in Biomedical Engineering (2001) and McKnight Endowment Fund Award for Technological Innovations in Neuroscience (2002). Dr. Ziaie is a member of the IEEE, American Association for the Advancement of Science, and the American Physical Society.