A Field-Deployable and Low-Cost PCR (FLC-PCR) Thermocycler for the Rapid Detection of Environmental E. coli.

This is a proof-of-concept study for the development of a field-deployable and low-cost PCR thermocycler (FLC-PCR) to perform Polymerase Chain Reaction (PCR) for the rapid detection of environmental E. coli. Four efficient (77.1 W) peltier modules are used as the central temperature control unit. One 250 W silicone heating pad is used for the heating lid. The PID (proportional-integral-derivative) control algorithm for the thermocycles is implemented by a low-cost 8-bit, 16 MHz microcontroller (ATMEGA328P-PU). ybbW and uidA genes from specific E. coli colonies were used as amplicons for the PCR reactions that were carried out by a commercial PCR machine (Bio-Rad) and our FLC-PCR thermocycler. The heating and cooling speeds averaged 1.11 ± 0.33°C/s which is on a par with the commercial bench-top PCR thermocycler and the efficiency of the heating lid outperformed the Bio-Rad PCR thermocycler. The overall cost of the system is lower than $200 which is more than ten times lower than commercially available units. The heating block can be customized to accommodate different PCR tubes and even microfluidic chambers. An 8000 W portable power generator will be used as the power supply for field studies.