The centrifuge. Almost every medical research laboratory has one, and it is probably one of the most generally identifiable pieces of lab equipment. The fundamental theory behind a centrifuge is to spin a sample in a circular plane fast enough in order to separate the heavier constituents – whatever they may be – from the lighter ones. For example, in 1864 Antonin Prandtl invented a centrifuge to separate cream from milk. Fifteen years later the first continuous centrifugal separator was developed and made commercially available. The basic operation of a centrifuge has not changed much since a hand-cranked version was first developed in the 18th century.
Until now. Researchers at UCLA and the California NanoSystems Institute have developed the “Centrifuge-on-a-Chip,” which does not rely on moving parts but instead on microfluidic dynamics principles – such as vortices generated in the chamber – to separate, sort, and trap cells. An individual chip processes sample flow rates of milliliters per minute and can be arranged in parallel with other chips to centrifuge larger samples faster. The researchers demonstrated proof of concept by “separating and concentrating cancer cells (diameter of 20 micrometers) from normal human blood cells (diameters range from 2 to 15 micrometers)” at a rate of 5 ml/min of diluted blood for a 2 square centimeter chip. Cell viability remained at greater than 90 percent, which is important for some of the applications that the researchers describe:
We envision this simple method may open opportunities in automated, low-cost and high-throughput sample preparation: (i) as an alternative to the standard benchtop centrifuge in resource poor settings, (ii) for streamlining standard cell-based diagnostics to reduce human error, or (iii) for large volume size-based cell separations.
We look forward to keeping you posted on any technologies developed as a result of “Centrifuge-on-a-Chip”!
Read about the miniature centrifuge in Lab on a Chip: Automated cellular sample preparation using a Centrifuge on a Chip.