Publications

Shediac, Renee S.; Barrett, Louise B.

Microfluidic devices have been proposed for 'Lab-on-a-Chip' applications for nearly a decade. Despite the unquestionable promise of these devices to allow rapid, sensitive and portable biochemical analysis, few practical devices exist. It is often difficult to adapt current laboratory techniques to the microscale because bench-top methods use discrete liquid volumes, while most current microfluidic devices employ streams of liquid confined in a branching network of micron-scale channels. The goal of this research was to use two phase liquid flows, creating discrete packets of liquid. Once divided into discrete packets, the packets can be moved controllably within the microchannels without loss of material. Each packet is equivalent to a minute test tube, holding a fraction from a separation or an aliquot to be reacted. We report on the fabrication of glass and PDMS (polydimethylsiloxane) devices that create and store packets.

Simmons, Blake S.; Shediac, Renee S.; Yang, Elaine L.

Abstract not provided.

Cummings, Eric B.; Simmons, Blake S.; Davalos, Rafael V.; Shediac, Renee S.; Mcgraw, Gregory J.

Abstract not provided.

Mcgraw, Gregory J.; Brazzle, John D.; Cummings, Eric B.; Shediac, Renee S.; Fintschenko, Yolanda F.; Davalos, Rafael V.; Ceremuga, Joseph T.; Chames, Jeffery M.; Hunter, Marion C.; Fiechtner, Gregory J.

We have successfully demonstrated selective trapping, concentration, and release of various biological organisms and inert beads by insulator-based dielectrophoresis within a polymeric microfluidic device. The microfluidic channels and internal features, in this case arrays of insulating posts, were initially created through standard wet-etch techniques in glass. This glass chip was then transformed into a nickel stamp through the process of electroplating. The resultant nickel stamp was then used as the replication tool to produce the polymeric devices through injection molding. The polymeric devices were made of Zeonor{reg_sign} 1060R, a polyolefin copolymer resin selected for its superior chemical resistance and optical properties. These devices were then optically aligned with another polymeric substrate that had been machined to form fluidic vias. These two polymeric substrates were then bonded together through thermal diffusion bonding. The sealed devices were utilized to selectively separate and concentrate a biological pathogen simulants. These include spores that were selectively concentrated and released by simply applying D.C. voltages across the plastic replicates via platinum electrodes in inlet and outlet reservoirs. The dielectrophoretic response of the organisms is observed to be a function of the applied electric field and post size, geometry and spacing. Cells were selectively trapped against a background of labeled polystyrene beads and spores to demonstrate that samples of interest can be separated from a diverse background. We have implemented and demonstrated here a methodology to determine the concentration factors obtained in these devices.

Shediac, Renee S.; Chames, Jeffery M.; Hachman, John T.; Ceremuga, Joseph T.; Brazzle, John D.; Fiechtner, Gregory J.; Cummings, Eric B.; Fintschenko, Yolanda F.

Abstract not provided.