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.