A comparison of thermocycling devices for automating the polymerase chain reaction

The polymerase chain reaction (PCR) has become a valuable tool in the fields of cellular and virological research. This paper presents a performance comparison of four devices (three commercial and one prototype) designed to supply the thermic cycle central to the PCR procedure. Results of investigations using a thermocouple revealed that the greatest heating rate and shortest cycle time was attained by the prototype device which used waterbaths as the conducting medium. Dry-block based systems, which heated and cooled a single thermal reservoir, provided generally smaller and more sophisticated machines, but two such devices produced varying results when subjected to experimental analysis. Before purchasing, it is recommended that comparative trials are conducted using differing types of machines, since performance may vary according to individual reactions executed.