A highly efficient means of microfluidic mixing has been created for use with the rHEALTH sensor — an elliptical mixer and passive curvilinear mixing patterns. The rHEALTH sensor provides rapid, handheld, complete blood count, cell differential counts, electrolyte measurements, and other lab tests based on a reusable, flow-based microfluidic platform.

These geometries allow for cleaning in a reusable manner, and also allow for complete mixing of fluid streams. The microfluidic mixing is performed by flowing two streams of fluid into an elliptical or curvilinear design that allows the combination of the flows into one channel. The mixing is accomplished by either chaotic advection around micro fluidic loops.

All components of the microfluidic chip are flow-through, meaning that cleaning solution can be introduced into the chip to flush out cells, plasma proteins, and dye. Tests were performed on multiple chip geometries to show that cleaning is efficient in any flow-through design. The conclusion from these experiments is that the chip can indeed be flushed out with microliter volumes of solution and biological samples are cleaned readily from the chip with minimal effort.

The technology can be applied in real-time health monitoring at patient’s bedside or in a doctor’s office, and realtime clinical intervention in acute situations. It also can be used for daily meas urement of hematocrit for patients on anticoagulant drugs, or to detect acute myocardial damage outside a hospital.

This work was done by Eugene Y Chan and Candice Bae of DNA Medicine Institute for Glenn Research Center. Inquiries concerning rights for the commercial use of this invention should be addressed to

NASA Glenn Research Center
Innovative Partnerships Office
Attn: Steve Fedor
Mail Stop 4–8
21000 Brookpark Road
Ohio 44135.

Refer to LEW-18391-1.

Medical Design Briefs Magazine

This article first appeared in the May, 2009 issue of Medical Design Briefs Magazine.

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