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

Abstract

We present a method of non-contact localized temperature measurement for determination of the non-uniformity of temperature distribution over a dPCR chip mounted on two different thermal cycling configurations.

Silicon as a microfluidic material for imaging and incubation of droplets

“…In both cases, the temperature measured by the Pt100 sensors fluctuated by less than ∼0.015°C over the course of ∼10 minutes (Figure S2). We also mapped the spatial profile of temperature actually sensed by the droplets with in situ DNA thermometers 49,56 . We measure a linear temperature gradient of 4.9 °C/cm, close to the nominal gradient imposed by the Peltier elements (5 °C/cm).…”

“…Those benefits have led Si to be used as substrate for industrial DNA synthesis 48 . Digital PCR in arrays of Silicon microchambers (where the PCR reaction is directly done in a micrometric Si chamber rather than in droplets) has been demonstrated – highlighting the good thermal performance of Silicon 49 .…”

An image-to-answer algorithm for fully automated digital PCR image processing

“…This technique was applied before in conjunction with DNA melting curve analysis for dPCR chip temperature non-uniformity determination. 43…”

“…This technique was applied before in conjunction with DNA melting curve analysis for dPCR chip temperature non-uniformity determination. 43 Here we conducted the following measurements to recognize and identify both NW and PW: adding the fluorescein with a concentration of ≈0.15 μM in the dPCR master mix, capturing the dPCR image using 16-bit resolution, and performing global non-uniformity corrections to reduce the non-uniform F value distribution of both PW and NW on the chip, thus inhibiting the false identification caused by non-uniform illumination.…”

Silicon chambers for enhanced incubation and imaging of microfluidic droplets

“…50 Digital PCR in arrays of Si microchambers (where the PCR reaction is directly done in a micrometric Si chamber rather than in droplets) has been demonstrated – highlighting the good thermal performance of Si. 51,52…”