N. Sergeev1 , A. Matviyenko2 , K. Herold2 , A. Rasooly3 , 1FDA/CDRH/OSEL/DB, Sliver Spring, MD, 2UMD-University of Maryland, College Park, MD, 3NIH-National Cancer Institute, Rockville, MD
Background: Polymerase Chain reaction (PCR) enables rapid and sensitive detection of microbial pathogens. Currently, PCR has a limited use for point-of-care diagnostics (POC) and in FDA's regulatory affairs mostly because PCR thermocyclers are designed as laboratory equipment requiring an external power source.
Methods: We developed a portable, battery powered PCR thermocycler employing a thin-film resistive heater and a regular computer fan for performing a rapid PCR in glass capillaries. Thermocycling conditions were controlled with computer-based pulse width modulation system. PCR (5µl) was performed in capillary cartridges placed on the top of the heating element. PCR amplicons were detected by in-capillary fluorescence and by gel electrophoresis.
Results: A prototype handheld, compact, rapid thermocycler was developed for multiplex analysis of nucleic acids in an inexpensive, portable configuration. The new thermocycler enable heating rates of 6-7 K/sec and cooling rates of 5 K/sec. The energy required by a nominal PCR cycle (20 sec at each temperature) was found to be 57 ±2 J yielding an average power of approximately 1.0 W (not including the computer and the control system). The 35 cycle PCR protocol using a single channel was completed in eighteen minutes. The prototype thermocycler was demonstrated for the detection of three pathogens (E. coli ETEC, Shigella dysenteriae and Salmonella enterica).
Conclusions: This prototype successfully demonstrates our concept of simple and efficient heating/cooling, low cost, rapid amplification, and low power consumption PCR thermocycler. The developed device is suitable for portable DNA amplification applications including clinical, POC diagnostics and field use.