Integrated Circuit/Microfluidic Chips for Dielectric Manipulation
Thomas P. Hunt, D. Issadore, K.A. Brown, Hakho Lee and R.M. Westervelt
from: Lab-on-a-Chip Technology (Vol. 2): Biomolecular Separation and Analysis (Edited by: Keith E. Herold and Avraham Rasooly). Caister Academic Press, U.K. (2009)
In this chapter, we describe the development of Integrated-Circuit/Microfluidic chips that can move individual living cells and chemical droplets along programmable paths using dielectrophoresis (DEP). These hybrid chips combine the biocompatibility of a microfluidic system with the complexity and programmability of an integrated circuit (IC), a microfluidic chamber is built directly on top of the IC and they offer new opportunities for sensing, actuation, and control. IC/Microfluidic chips can independently control the location of hundreds of dielectric objects, such as biological cells or chemical droplets, in the microfluidic chamber at the same time. The IC couples with suspended objects by using spatially patterned, time-dependent electromagnetic fields. The IC layout is similar to a computer display: it consists of a two-dimensional array of 128x256 metal 'pixels', each 11x11 μm2 in size, controlled by a built-in SRAM memory. Each pixel can be energized by a radio frequency (RF) voltage up to 5 Vpp. The ICs were made in a commercial foundry, and a microfluidic chamber was built on its top surface at Harvard. Using this IC/Microfluidic chip, we have moved yeast and mammalian cells along programmed paths at speeds up to 300 μm/sec. Hundreds of cells can be individually trapped and simultaneously positioned into controlled patterns. The chip can trap and move pL droplets of water in oil, split one droplet into two, and mix two droplets into one, allowing one to conduct experiments with chemicals and individual cells, using tiny amounts of fluid. Our IC/Microfluidic chip provides a programmable platform that can individually control the motion of large numbers of cells and fluid droplets simultaneously for lab-on-a-chip applications read more ...