A novel circular ferrofluid driven microchip has been developed for rapid polymerase chain reaction (PCR). A closed-loop circular channel was fabricated on one microchip and the PCR mixture together with a small ferrofluid plug was injected into the loop. An external magnet is used to drive the ferrofluid plug, which in turn propels the PCR mixture to move around and flow continuously through three pre-set temperature zones.

Parameters of PCR, such as incubation time, temperatures and number of cycles, can be fully controlled and adjusted. To improve throughput, a multi-loop ferrofluid driven microchip was also developed by designing a series of concentric circular channels on one microchip and the magnet enabled simultaneous actuation of DNA samples in all the channels. High reproducibility was achieved for different channels in the same run and for the same channels in consecutive runs.

The circular ferrofluid-driven PCR microchips combine the cycling flexibility of the chamber PCR and the quick temperature transitions associated with the continuous flow (CF) PCR. Most importantly, the small footprint and simultaneous actuation make it the right candidate for parallel PCR analysis. The simple, reliable and high-throughput PCR microchips will find wide applications in forensic, clinical and biological fields.

from Sun et al in Lab-on-a-Chip Technology (2009) Herold KE and Rasooly A (eds) Published by Caister Academic Press

Further reading:

• Lab-on-a-Chip Technology
• Biomolecular Separation and Analysis

Labels: lab on a chip, microchip, microfluidics, rapid PCR, technology