US Patent 7252928 - Reducing microchannel adsorption using colloidal material flow

http://www.freepatentsonline.com/7252928.html

When using microfluidic devices to analyze biological materials such as proteins a problem can occur of the material being adsorbed in the microchannel walls. This patent from Caliper Life Sciences teaches adding a colloidal material flow which binds to the biological material reducing the adherence to the channel walls. Claim 1 reads:

1. A method of reducing adsorption of one or more materials to an interior surface of a microchannel, the method comprising flowing the one or more macromolecules in a fluid in the microchannel, and concomitantly flowing a colloidal material through the fluid in the microchannel at a sufficient concentration to bind to the one or more materials and thereby prevent the materials from binding to the interior surface of the microchannel.

US Patent 7214427 - Quantum dot tag subject to microfluidic control

http://www.freepatentsonline.com/7214427.html

Electrophoretic pumping is a method using electric fields to move minute quantities of fluid applicable to biological and chemical analysis. This patent from Aviva Biosciences teaches the formation of beads to facilitate such pumping and which can also be used as quantum dot tags for tracking particular biofluids. Claim 22 reads:

22. A bead, which bead comprises: a) a magnetizable substance; and b) an electrically conductive substance, and a quantum dot.

US Patent 7179383 - Magnetomotive microfluidics

http://www.freepatentsonline.com/7179383.pdf

Most microfluidic flow control systems used in biological processing rely on electrostatic based flow processing (electrophoresis, electroosmotic, EHD, etc.) However, this patent from Iowa State University teaches a magnetic field based flow control that may be used in combination with GMR (giant magnetoresistance) detection of magnetically labeled analytes. Claim 1 reads:

1. A method to move a magnetizable object along a microfluidic channel comprising the step of generating a local magnetic field gradient in conjunction with a uniform magnetic field in the presence of the magnetizable object.