The UPF40 module can pump a heat flux up to 80 W/cm2 at 25 degrees C producing a smaller footprint.

Recent developments in thin-film thermoelectric materials could provide significant benefits for future medical device developments, especially in addressing DNA applications. This stems from a report issued by Nextreme Thermal Solutions citing an ability to demonstrate the application of thin-film thermoelectric devices for temperature control of the polymerase chain reaction (PCR) process used in DNA amplification. According to the company, the microscopic size and millisecond response time of their new material’s thermoelectric modules will shorten throughput times for DNA sequencing equipment.

The short cycle time temperature control uses two eTEC UPF40 thermoelectric modules that perform as microscopic heat pumps. The module uses the thermoelectric effect to heat or cool objects simply by changing the direction of current flow. A UPF40 module can pump a heat flux up to 80 W/cm2 at 25 degrees C with a 0.650 mm profile and a smaller 2.5mm X 5.1 mm footprint. Additionally, 4.1 watts of cooling and heating occur with less than a 2 msec response time at the device level.

PCR is a technique widely used in molecular biology to produce millions of copies of a specific DNA sequence in a short period of time. PCR-based testing is used in the diagnosis of hereditary diseases; the identification of genetic fingerprints (used in forensic sciences and paternity testing); and the detection and diagnosis of infectious diseases. The vast majority of PCR methods use thermal cycling, i.e., alternately heating and cooling of the DNA sample based on a pre-defined series of temperature steps.

A thermal cycler is an automated instrument specifically designed for this purpose. A typical device consists of a metal block with holes where plastic vials holding the PCR reaction mixtures are inserted. The instrument has an integrated heating/cooling unit that is used to systematically raise and lower the temperature of the block.

According Nextreme’s thermoelectric devices have a low mass making it well suited to achieve fast temperature changes while also achieving a uniform temperature distribution throughout the block. In addition, the microscopic size enables different temperatures in different parts of the block. This is particularly useful when testing suitable annealing temperatures for primers, which are required for initiation of the DNA replication sequence.