Injection and flow control system for microchannels

Abstract

In spite of considerable efforts, flow control in micro-channels remains a challenge owing to the very small ratio of channel/supply-system volumes, as well as the induction of spurious flows by extremely small pressure or geometry changes. We present here an inexpensive and robust system for flow control in a microchannel system, based on a dynamic control of reservoir pressures at the end of each channel. This system allows flow equilibration with a time constant smaller than one second, and is also able to maintain stable flux from stopped flow to many microl min(-1) range over several hours. It is robust to changes in ambient pressure and temperature. This system further includes a feature for sub-microliter sample injection during the experiment. We quantify flow control in elastomer and thermoplastic channels, and demonstrate the impact on one application of the system, namely the reproducible, automated separation of large DNA by electrophoresis in a self-organized magnetic bead matrix in a microchannel.

New shells for magnetic nanoparticles based on polypyrrole functionalized with α-amino acids

“…[19][20][21][22] For many medical and biomedical applications it is essential to functionalize their surface. The functions can be directly attached to the magnetic nanoparticles by adsorption or by using polymers, such as polypyrrole (PPy).…”

Improved hydrostatic pressure sample injection by tilting the microchip towards the disposable miniaturized CE device

“…Solignac and Gijs [11] developed a system in which the samples were injected hydrodynamically by applying pressure pulse to a membrane on the reservoir using mechanical actuator. Futterer et al [12] reported an injection system based on dynamic control of the reservoir pressures at the end of each channel. Wu et al [13] proposed a sample introduction method based on push/pull pressure flow using dual-syringe pump with switching valve.…”

Surface treatment and characterization: Perspectives to electrophoresis and lab‐on‐chips

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“…Nowadays, the interest of researchers in bioanalysis is turning toward microfluidic devices, or "lab-on-a-chip" systems. This field has stimulated "extremely fertile imaginations", including several aspects including fluid flow control [1][2][3], chip microfabrication, and architecture [4]. As compared with CE, microfabricated systems provide much more flexibility in their design, since complex channel networks can be made without the complexity and dead volumes of capillary connectors.…”