New Miniaturized Device for Lab-on-a-Chip Separations

Researchers at the National Institute of Standards and Technology (NIST) have developed an elegantly simple, miniaturized technique for separating minute samples of proteins, amino acids and other chemical mixtures.

A prototype device can run up to eight separations simultaneously in a space about the size of a quarter, highlighting the technique's potential for use in microfluidic lab-on-a-chip systems.

The NIST technique, "gradient elution moving boundary electrophoresis" (GEMBE), works by opposing the movement of the mixture's components with a stream of buffering solution flowing at a variable rate.

GEMBE is suited for use in microfluidic lab-on-a-chip devices. Components are selected by buffer flow-rate rather than distance, so the channel can be very short--less than a centimeter in NIST prototypes.

The technique has been validated at NIST with separations ranging from small dye molecules and amino acids to larger biomolecules, such as DNA. A prototype eight-channel GEMBE device built at NIST can produce a complete immunoassay calibration curve for insulin in a single run. NIST is applying for a patent on the method.