Thermoelectric coolers speed up PCR testing

09-02-2022 | Laird | Subs & Systems

Thermal Cycling devices employed for real-time PCR use thermoelectric technology to precisely manage temperature set points and ramp rates, facilitating amplification of DNA segments. Laird Thermal Systems has created an elongated series of PowerCycling PCX thermoelectric coolers to enhance temperature precision control in PCR devices. Using proprietary processes and a unique module construction, the PCX Elongated Series delivers high reliability and a minimal temperature gradient for PCR applications producing greater throughput and faster test results.

PCR demands many thermal cycles to create millions of DNA strands utilised for medical diagnosis. Each thermal cycle comprises three steps, where the first separates the DNA strands at a high temperature of 95C. The second step is a cool down to a melt temperature between 50C to 65C, where the biomarkers can bond to the DNA, and the third stage increases the temperature to 72C to sequence a copy of the DNA. Thermoelectric coolers are installed under the PCR wells to exactly manage these temperature setpoints to within ±0.5C.

Defining the optimum melt temperature of each thermal cycling stage is frequently a time-consuming process for laboratory technicians. The optimal melt temp can be discovered by creating more temperature zones on the PCR tray. The new series offers more narrow temperature zones than standard thermoelectric coolers. It delivers more precise temperature control over the tray, making it simpler for technicians to define the right temperature.

“Elongated thermoelectric coolers are extremely challenging to manufacture due to the bowing effect that can occur with longer parts. The longer the length is to the width, the more likely the ceramics tend to bow, which can be challenging to manufacture,” said Andrew Dereka, product director at Laird Thermal Systems. “Through proprietary process controls and advanced semiconductor materials, our PCX Elongated thermoelectric cooler eliminates the impact of this effect to provide a highly reliable part for Real-Time PCR.”

The series provides a unique, robust construction with a thermally conductive 'soft layer' that absorbs the mechanically induced stresses created by thermal cycling applications. This series has been tested to satisfy the latest PCR industry standards with no performance degrade.

By Natasha Shek