Researchers from The Methodist Hospital Research Institute and MD Anderson Cancer Center developed and tested a new microfluidic device that can rapidly perform a blood screening for up to 50 biomarkers in one go.
Tests can be done for protein antibodies, DNA or RNA fragments, and lipids, and by building a larger chip with more passageways the number of tests can be further increased. The chip works by forcing a reaction to occur within each vertical well which in turn pushes a dye up the channel. Because the distance that the dye travels is proportional to the concentration of the substance being looked at in that well, it provides a quick and easy readout that doesn’t need additional equipment to interpret.
The V-Chip could make it possible to bring tests to the bedside, remote areas, and other types of point-of-care needs,” said Nanomedicine faculty member Lidong Qin, Ph.D., the project’s principal investigator. “V-Chip is accurate, cheap, and portable. It requires only a drop of a sample, not a vial of blood, and can do 50 different tests in one go.
Similar assays are typically done using heavy, large, complex equipment such as mass spectrometers, or require fluoroscopy analysis, which must also be done in a lab.
In between are wells for four things: (1) hydrogen peroxide, (2) up to 50 different antibodies to specific proteins, DNA or RNA fragments, or lipids of interest, and the enzyme catalase, (3) serum or other sample, and (4) a dye — any dye will do. Initially, the wells are kept separate from each other. A shift in the glass plates brings the wells into contact, creating a contiguous, zig-zagged space from one end of the V-chip to the other.
Binds to antibodies bound to the glass slide, catalase is made active and splits nearby hydrogen peroxide into water and oxygen gas. This approach is called ELISA, or enzyme-linked immunosorbent assay. The oxygen pushes the dye up the column. The more present insulin is, the more oxygen is created, and the farther dye is pushed up the slide. Tests show that distance is more or less proportional to the amount of substrate present, in this example, insulin. The end result is a visual bar chart.