Weaponized biological agents are as great a threat as nuclear or chemical weapons. They must be detected at the earliest
stage to prevent diffusion because once these agents are dispersed into the air, the rapidly decreasing concentration
makes detection more of a challenge. Polymerase chain reaction (PCR) is a common method to create copies of a
specific target region of a DNA sequence and to produce large quantities of DNA molecules. A few DNA molecules are
rapidly amplified by PCR into billions of copies. While PCR is a powerful technique and is capable of countering new
threats relatively easily, it is plagued by the number of processes necessary. Therefore, we have developed an integrated
PCR system for rapid detection of biological agents captured from the air. Each processing function is performed by a
dedicated module, and reduction in the process time has been made the top priority, without loss in the signal/noise ratio
of the total system. Agents can be identified within 15 min from capture. A fully automated operation protects operators
from exposure to potentially highly lethal samples.
Polymerase chain reaction (PCR) is a common method used to create copies of a specific target region of a DNA
sequence and to produce large quantities of DNA. A few DNA molecules, which act as templates, are rapidly amplified
by PCR into many billions of copies. PCR is a key technology in genome-based biological analysis, revolutionizing
many life science fields such as medical diagnostics, food safety monitoring, and countermeasures against bioterrorism.
Thus, many applications have been developed with the thermal cycling. For these PCR applications, one of the most
important key factors is reduction in the data acquisition time. To reduce the acquisition time, it is necessary to decrease
the temperature transition time between the high and low ends as much as possible. We have developed a novel rapid
real-time PCR system based on rapid exchange of media maintained at different temperatures. This system consists of
two thermal reservoirs and a reaction chamber for PCR observation. The temperature transition was achieved within 0.3
sec, and good thermal stability was achieved during thermal cycling with rapid exchange of circulating media. This
system allows rigorous optimization of the temperatures required for each stage of the PCR processes. Resulting
amplicons were confirmed by electrophoresis. Using the system, rapid DNA amplification was accomplished within 3.5
min, including initial heating and complete 50 PCR cycles. It clearly shows that the device could allow us faster
temperature switching than the conventional conduction-based heating systems based on Peltier heating/cooling.