Temperature non-uniformity detection on dPCR chips and temperature sensor calibration

Area of Science:

• Biotechnology
• Microfluidics
• Analytical Chemistry

Background:

• Precise temperature control is crucial for microfluidic digital polymerase chain reaction (dPCR) efficiency.
• Measuring temperature distribution within dPCR chips non-invasively is challenging.
• Existing methods like fluorescein-based measurements can suffer from photobleaching.

Purpose of the Study:

• To develop a non-contact method for localized temperature measurement in dPCR chips.
• To characterize temperature non-uniformity within dPCR devices.
• To enable calibration of temperature sensors and enhance dPCR system precision.

Main Methods:

• Utilized a PCR solution with a known melting temperature (Tm) as an internal temperature sensor.
• Heated the dPCR chip and captured fluorescent images of partitions.
• Calculated localized Tm values from fluorescence intensity vs. temperature plots to create a 3-D temperature map.

Main Results:

• Demonstrated that measured Tm values varied across the dPCR chip, indicating temperature non-uniformity.
• Successfully mapped the distribution of temperature variations within the dPCR chip.
• The Tm-based method provided internal temperature distribution, unlike surface-only measurements.

Conclusions:

• The developed Tm-based method accurately characterizes temperature non-uniformity in dPCR chips without physical contact.
• This approach avoids photobleaching issues associated with other methods.
• The technique is applicable to other microarray systems requiring non-invasive temperature uniformity assessment and can improve dPCR performance.