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Sandia Technology logo A quarterly research and development magazine.

Winter 2006/2007
Volume 8, No. 4

SANDIA TECHNOLOGY

biotoxin system
LDRD logo





Expanding researcher access to microfluidic fittings

ron renzi
Inventor Ron Renzi in his lab with an integrated biotoxin analysis system with an automated sample preparation front end. (Photo by Jeff Shaw)
“It’s the only time at Sandia I’ve seen anything propagate like this,“ says inventor Ron Renzi, a Sandia microsystems engineering researcher. “It’s amazing how well-received these technologies have been.” The tool set he’s referring to, a kind of micro-plumbing set, was developed by a Sandia team, simply because nothing else was available.

The suite was developed during the initial stages of a MicroChemLab Laboratory Directed Research and Development (LDRD) Grand Challenge program, Renzi says, when he could not find commercially available components to easily form fluidic seals in small spaces. MicroChemLab was designed to enhance traditional wet-bench chemical analysis of such threats as trace explosives and biotoxins by rapidly and portably separating samples on chips under an applied voltage.

With the help of Art Pontau, senior manager of the Materials and Energy Sciences group, and Jim Wilhelm, who handled the licensing agreement, the fittings were licensed late last year to LabSmith, a Livermore, California-based hardware company formed by former Sandia researchers Eric Cummings and Kirsten Pace.

Working on the initial MicroChemLab project eight years ago with Mark Claudnic and Tom Raber, the team developed the first component, called CapTite — a one-piece ferruled fitting with thread connections for sealing to thin, flexible capillaries. This solved the problem of getting fluids to microchannels on chips in a way that prevents troublesome leaks or bubbles.

biotoxin analysis system
Inventor Ron Renzi in his lab with an integrated biotoxin analysis system with an automated sample preparation front end. (Photo by Jeff Shaw)
The next year, manifolds and interfaces that provide consistent fluid connections with simple and accurate alignment were developed.

Microthruster development

One example of an application is the LDRD-funded microthruster development, where designs are being explored for using propellants in nanosatellites. These small satellites can be used for communications, surveillance, or networking. The fittings allow different configurations to be tested, so that mixing an oxidizer to increase thrust can be investigated. Liquid propellants are moved using electrokinetic pumping, in which an electric field causes flow of a liquid in a packed bed. The flow reaches the closed end of a capillary and drives a reverse, pressure-driven flow that can be tailored to the application by altering the size of particles in the packed bed.

Several patents have been issued or applied for with the assistance of Sandia’s Scott Ferko, a coinventor of the patented one-piece ferrule. Patents awarded so far include those associated with compression manifolds, microvalves, and high-pressure fittings. The fitting is capable of withstanding pressures up to 40,000 psi and can be used in smaller versions of the standard benchtop analytical tool, liquid chromatography systems requiring 10,000 psi.