Eric T. Lagally

Monolithic membrane valves and diaphragm pumps for practical large-scale integration into glass microfluidic devices

Abstract Monolithic elastomer membrane valves and diaphragm pumps suitable for large-scale integration into glass microfluidic analysis devices are fabricated and characterized. Valves and pumps are fabricated by sandwiching an elastomer membrane between etched glass fluidic channel and manifold wafers. A three-layer valve and pump design features simple non-thermal device bonding and a hybrid glass-PDMS fluidic channel; a four-layer structure includes a glass fluidic system with minimal fluid-elastomer contact for improved chemical and biochemical compatibility. The pneumatically actuated valves have

Monolithic integrated microfluidic DNA amplification and capillary electrophoresis analysis system

Abstract A monolithic integrated DNA analysis system comprised of microfluidic valves and vents, PCR amplification chambers, and capillary electrophoretic separation channels has been microfabricated in a glass sandwich structure. Valves and hydrophobic vents provide controlled and sensorless sample loading into 280 nl PCR chambers; the low volume reactor and the use of thin film heaters permit thermal cycle times as fast as 30 s. The amplified product is labeled with an intercalating fluorescent dye and directly injected into a microfabricated capillary electrophoresis channel. Analyses with this device have produced and detected PCR products from reactions with as few as 20 starting DNA template copies/μl, (five to six copies/chamber). The extrapolated limit of detection based on data using 20 cycles is two copies/chamber. The optimization of heater placement, thermal anisotropy measurements, and the optimization of thermal profiles are also discussed.

Fully integrated PCR-capillary electrophoresis microsystem for DNA analysis

A fully integrated genomic analysis microsystem including microfabricated heaters, temperature sensors, and PCR chambers directly connected to capillary electrophoretic separation channels has been constructed. Valves and hydrophobic vents provide controlled and sensorless sample positioning and immobilization into 200 nL PCR chambers. The use of microfabricated heating and temperature sensing elements improves the heating and cooling rates for the PCR reaction to 20 degree C s(-1). The amplified PCR product, labeled on-column with an intercalating fluorescent dye, is injected into the gel-filled capillary for electrophoretic analysis. Successful sex determination using a multiplex PCR reaction from human genomic DNA is demonstrated in less than 15 min. This device is an important step toward a microfabricated genomic microprocessor for use in forensics and point-of-care molecular medical diagnostics.

Integrated PCR-CE System for DNA Analysis to the Single Molecule Limit

We have developed an integrated PCR-CE system for DNA amplification and analysis from nanoliter volumes with single molecule sensitivity. In addition, thermal cycling elements have been microfabricated directly onto the device for improved thermal cycling efficiency. PCR-CE data demonstrating sex determination from human genomic DNA are presented.

Practical Valves and Pumps for Large-Scale Integration into Microfluidic Analysis Devices

Pneumatically-actuated elastomer membrane valves and pumps for practical large-scale integration into glass μTAS devices are fabricated and characterized. The valves and pumps reliably manipulate nanoliter-scale volumes of fluid, introduce low dead volumes into the microfluidic system, and are compatible with a wide range of device chemistries. The integrated pneumatic manifold and practical microfabrication process facilitate the production and use of high-density arrays of the valves and pumps.

Monolithic integrated PCR reactor-CE system for DNA amplification and analysis to the single molecule limit

A fully integrated genomic analysis microsystem including heaters, temperature sensors, and polymerase chain reaction (PCR) chambers directly connected to capillary electrophoresis (CE) separation channels has been developed. The device utilizes pneumatic valves and hydrophobic vents for positive and sensorless sample loading and immobilization within 200 nL PCR chambers. Use of microfabrication techniques for the creation of resistive heating and temperature-sensing elements has improved the thermal response and accuracy of the system beyond previous limits. Amplified PCR products are labeled on-column with a fluorescent intercalating dye and injected into a gel-filled microchannel for electrophoretic analysis. Successful sex determination by performing multiplex PCR from human genomic DNA is demonstrated in under 15 minutes.

Microfabrication Technology for Chemical and Biochemical Microprocessors

We have developed two key technologies necessary for the fabrication of fully-integrated DNA analysis microprocessors. Submicroliter PCR reactors directly coupled to separation microchannels provide integrated DNA amplification and capillary electrophoresis analysis. Novel microchannel turn geometries for the fabrication of folded separation channels provide increased device performance and feature density.