Experiments show that particles smaller than the throat size of converging-diverging microchannels can sometimes be trapped near the throat. This critical phenomenon is associated with the negative dc dielectrophoresis arising from nonuniform electric fields in the microchannels. A finite-element model, accounting for the particle-fluid-electric field interactions, is employed to investigate th...

We apply a recent extension of the Hele-Shaw scheme to analyze steady compressible viscous flows through micro T-junctions. The linearity of the problem in terms of an appropriately defined quadratic form of the pressure facilitates the definition of the viscous resistance of the configuration, relating the gas mass-flow rate to entrance and exit conditions. Furthermore, under rather mild restr...

A simple method to fabricate microchannels is demonstrated based on an inkjet printing liquid template. The morphology of the liquid template can be well controlled by using ink with viscosity sensitive to temperature. The as-prepared Y-shape microchannel is used as a microfluidic reactor for an acylation fluorigenic reaction in a matrix of polydimethylsiloxane (PDMS). Arbitrary modification of...

We investigated the shape of the liquid-liquid interface in micro counter-current flows formed within microchannels. The pressure balance at the interface was calculated based on the interface geometry. Although the shape should be an arc under laminar flow, a large deformation near the center of the microchannel was observed. In the center of the microchannel, Laplace pressure (171 - 450 Pa) w...

Particle manipulation represents an important and fundamental step prior to counting, sorting and detecting bioparticles. In this study, we report dean-coupled inertial focusing of particles in flows through a single curve microchannel at extremely high channel Reynold numbers (~325). We found the lateral particle focusing position, xf to be fixed and largely independent of radius of curvature ...

One of the key biological materials that can be used for disease diagnosis is the blood. The first step to examine the blood is separation of molecules in blood. In this work, the meander structure based microfluidic channel with different dimensions is designed for filtering applications. The performance characteristic of microchannel is analysed for symmetric and asymmetric geometries. The ge...

This paper presents micromachined thermal sensors for measuring liquid flow rates in the nanoliter-per-minute range. The sensors use a boron-doped polysilicon thinfilm heater that is embedded in the silicon nitride wall of a microchannel. The boron doping is chosen to increase the heater’s temperature coefficient of resistance within tolerable noise limits, and the microchannel is suspended fro...

Microfluidic devices are a promising new tool for studying and optimizing (bio)chemical reactions and analyses. Many (bio)chemical reactions require accurate temperature control, such as for example thermocycling for PCR. Here, a new integrated temperature control system for microfluidic devices is presented, using chemical and physical processes to locally regulate temperature. In demonstratio...

ABSTRUCT This paper demonstrates a method to form and fuse spheroids on a microfluidic chip without cell labeling nor specific pattern of a microchannel. Label-free magnetic cell manipulation became possible by adding a paramagnetic salt into culturing medium to enhance the diamagnetic property of the cells. Cells in the paramagnetic medium were aggregated ultrarapidly within a microchannel by ...

The modelling, simulation, fabrication and testing of a microchannel cooling plate are described in this article. The cooling component is to be used in microelectronic packaging applications. The nickelbased micro-channel cooling plate is fabricated on a glass substrate using a two-layer electroforming process borrowed from UV-LIGA. Forced convection of air or liquid is scheduled for this micr...