Seminar: April 15th, 4-5 PM, Allen 101X - Lithographically-Patterned Self-Assembling and Chemo-Mechanical Devices

Seminar:  Lithographically-Patterned Self-Assembling and Chemo-Mechanical Devices

Wednesday, April 15, 2008
4:00 – 5:00 pm
Allen 101X (formerly known as CISX-101)

David Gracias

Assistant Professor, Departments of Chemical and Biomolecular Engineering, Chemistry and the Institute for Nanobiotechnology
The Johns Hopkins University

Abstract:
Optical and electron beam lithography allow precise patterning on the micro-nanoscale; these paradigms are routinely utilized to construct a variety of electronic, optical and biomedical devices in two (and quasi-three) dimensions. In this talk, I will describe strategies that utilize lithographic multilayer patterning to construct 2D structures that self-assemble and show chemically-responsive functionality. Specifically, I will describe the construction of 3D patterned polyhedral structures with sizes ranging from the nanoscale to the mm-scale; and give examples of their utilization in reconfigurable microfluidics and cell therapy. I will also describe strategies wherein lithography and material properties (moduli and stress) are both engineered to enable spontaneous assembly of complex 3D structures like spirals, coils and cylinders. Finally, as a step toward the construction of autonomous and Micro Chemo-Mechanical Systems (MCMS), I will discuss lithographically patterned and chemically responsive functional microgrippers. As opposed to electrical or pneumatic signals typically used to actuate conventional microtools; these grippers close and open in when exposed to specific chemicals (without the need for any batteries, tethers or wiring). The grippers were utilized to pick-and-place objects and to enable an in vitro surgical biopsy.

Bio:
David Gracias received an integrated 5 yr MS degree from IIT Kharagpur and a Ph.D. in physical chemistry from UC Berkeley in 1999. After completing post-doctoral studies on self-assembling electronic systems at Harvard in 2001, he was a Senior Integration Engineer at Intel Corporation (Hillsboro, OR). He joined the Johns Hopkins University in the fall of 2003. His current research is focused on self-assembly, MEMS / NEMS, non-linear optics, organic electronics, drug delivery and nanomedicine. He has published over 50 papers and holds 18 issued U.S. patents, with several others pending. His awards include the NIH Directors New Innovator Award, DuPont Young Professor Award, Beckman Young Investigator Award, Dreyfus Teacher Scholar Award and the NSF Career Award.