Blood component separation in straight microfluidic channels.

Separation of blood components is required in many diagnostic applications and blood processes. In laboratories, blood is usually fractionated by manual operation involving a bulk centrifugation equipment, which significantly increases logistic burden. Blood sample processing in the field and resource-limited settings cannot be readily implemented without the use of microfluidic technology.

Label-free enrichment of human adipose-derived stem cells using a continuous microfluidic sorting cascade.

Human adipose tissue is a rich source of mesenchymal stem cells (MSCs). Human adipose-derived stem cells (ADSCs) are first prepared by tissue digestion of lipoaspirate. The remaining constituent contains a mixture of ADSCs, other cell types and lysed fragments.

Super-Period Gold Nanodisc Grating-Enabled Surface Plasmon Resonance Spectrometer Sensor.

We experimentally demonstrate a surface plasmon resonance spectrometer sensor by using an e-beam-patterned super-period gold nanodisc grating on a glass substrate. The super-period gold nanodisc grating has a small subwavelength period and a large diffraction grating period. The small subwavelength period enhances localized surface plasmon resonance, and the large diffraction grating period diffracts surface plasmon resonance radiation into different directions corresponding to different wavelengths.

On-chip micromanipulation and assembly of colloidal particles by electric fields.

We overview the ways in which electric fields can be used for on-chip manipulation and assembly of colloidal particles. Particles suspended in water readily respond to alternating (AC) or direct current (DC) electric fields. Charged particles in DC fields are moved towards oppositely charged electrodes by electrophoresis.

An AC electrokinetic technique for collection and concentration of particles and cells on patterned electrodes.

We report an electrohydrodynamic effect arising from the application of alternating electric fields to patterned electrode surfaces. The AC fields were applied to dilute suspensions of latex microspheres enclosed between a patterned silicon wafer and an ITO-coated glass slide in a small chamber. The latex particles became collected in the center of the conductive "corrals" on the silicon wafer acting as bottom electrode.

Control and modeling of the dielectrophoretic assembly of on-chip nanoparticle wires.

Suspensions of metallic nanoparticles in water were assembled via the action of an alternating electric field (dielectrophoresis) into wires of micrometer thickness. Two modes of microwire assembly, one through the bulk of the suspension and one as half-cylinders on the glass surface between the electrodes, were identified. The operating conditions responsible for the two assembly modes were recognized.

Anisotropic particle synthesis in dielectrophoretically controlled microdroplet reactors.

The miniaturization of chemical and biological processes in microfluidic devices and bioarrays is a major technological achievement. Microchips performing multiphase material synthesis operations could be a future step in this trend of miniaturizing technology. Here we show how electrically controlled chips can be used for the synthesis and manipulation of new types of particles with advanced structure.