Microfluidic sedimentation cytometer for milk quality and bovine mastitis monitoring.

We report a rapid, low-cost, portable microfluidic sedimentation cytometer (SeCy) for assessing the somatic cell count and fat content of milk in 15 min using a "sample-in, answer-out" approach. The system consists of 12 independent microfluidic devices, essentially flattened funnel structures, fabricated on the footprint of a single plastic compact disc (CD). Each funnel structure holds 150 μL of milk, has an inlet for milk filling and an outlet for air to escape, and ends in a narrow, closed-end microfluidic channel that facilitates packing of the cells into a column whose length is proportional to cell count.

Rapid microchip-based electrophoretic immunoassays for the detection of swine influenza virus.

Towards developing rapid and portable diagnostics for detecting zoonotic diseases, we have developed microchip-based electrophoretic immunoassays for sensitive and rapid detection of viruses. Two types of microchip-based electrophoretic immunoassays were developed. The initial assay used open channel electrophoresis and laser-induced fluorescence detection with a labeled antibody to detect influenza virus.

Dielectrophoretic manipulation of particles and cells using insulating ridges in faceted prism microchannels.

This paper presents a novel device for the dielectrophoretic manipulation of particles and cells. A two-level isotropic etch of a glass substrate was used to create three-dimensional ridge-like structures in micrometer-sized channels. Due to the insulating properties of glass, locally patterned regions of nonuniform electric field form near the ridges when a dc field is applied along the channel.

Fabrication and analysis of spatially uniform field electrokinetic flow devices: theory and experiment.

A uniform-field design approach can improve the performance of microanalytical, chip-based devices for a number of applications, including separations and sample preparation. The faceted prism paradigm allows the design of microfluidic devices possessing spatially uniform fields in electrokinetically driven flows. We present the first quantitative study of the velocity fields obtained using faceted interfaces between deep and shallow channel sections.