Cascade Microtech Inc. pledges to put microfluidic-chip testing on a par with the testing of microelectronics. "High precision is what we do best, and our microfluidic systems provide that same caliber of precision metrology as our microelectronic metrology systems," said Cali Sartor, senior program manager for Cascade's L-Series tester. "Our L-Series will not only test your microfluidics chip more quickly, but the results themselves will be much higher-precision and more repeatable."
Founded in 1983, the company has maintained its leadership in microelectronics testing by continually staying one step ahead of the market's needs. Now, "We want to stay ahead in microfluidics metrology by continuing to innovate," said Akshay Gupta, director of marketing. "We want to make our microfluidic metrology systems indispensable to lab-on-chip developers."
The company says its microfluidics metrology supplies the infrastructure and standards necessary to accelerate lab-on-chip device development for medical diagnostics, therapeutics, drug discovery and ecological monitoring. The L-Series systems sell for $5,000 to $85,000.
The high-precision positioning possible with wafer probes Cascade Microtech's stock in trade made it easy for the Beaverton, Ore., company to craft precision "microports" for fluidic input/output. "If you use the L-Series throughout your design cycle, you can do the kinds of things you do with our wafer probes, but for microfluidic chips," Sartor said. "For instance, you can validate the functioning of microfluidic chips nondestructively by just attaching our microports. Our metrology will then help you characterize your microfluidic component and the functions of your lab-on-chip, as well as validate the complete end-user system by integrating the microfluidics with the microelectronics."
"When we started out in microelectronics, engineers had to cut their chips out of a wafer just to test them, but when they started using our wafer probes they found they could get more consistent and accurate measurements. It's the same deal in microfluidics," said co-founder Reed Gleason, now the vice president of advanced development at Cascade Microtech. "Today, when two microfluidic chips don't test out the same, you don't know if it's the chip or just because you glued the connection onto one of them poorly. The L-Series will enable bioengineers to use the same microport for both chips, so the measurement will be more reliable and consistent."
The L-Series can deliver fluid to a microfluidic device for pressure pumping, electro-osmotic pumping, low-voltage dielectrophoresis, and electrophoretic separation and mixing. The system standardizes on two types of removable microports: one for fluidic connections and one for electrode-only connections. Both are reusable but are inexpensive enough to be disposable.
Each microport can deliver or receive fluid, electricity or both, and each can accommodate 200-psi pressure pumping and up to 5 kV for electro-osmotic pumping or electrophoretic flows. The system provides a visual stage with a 50-mm field of view, permitting optical viewing of the assay throughout an experiment.
This means microfluidic chips don't have to be fabricated with embedded test electrodes. Nor do they require fastening areas that break off after testing, because Cascade Microtech's fluid and electrical connectors can be attached and moved as easily as one of its wafer or printed-circuit-board probes.
Also, common experimental problems, such as getting ride of air bubbles, are eliminated, according to Cascade. "I've been in labs where it took three hours to remove an air bubble from a manifold test fixture. That's why we designed microports with a valve that bleeds off any air bubbles," said Gleason.