Programmable Peltier-block instrument cycling reaction temperatures for polymerase chain reaction (PCR) DNA amplification and qPCR transcript quantification.
Specifications & Metrics
measures
Exponential DNA amplification and real-time fluorescence threshold cycle (Ct / Cq) mRNA quantification
Core Principles & Analysis
Following Kary Mullis's invention of the polymerase chain reaction (PCR) and the adoption of thermostable Taq DNA polymerase from Thermus aquaticus, modern thermal cyclers use solid-state Peltier heat pumps and silver or aluminum blocks to ramp rapidly between denaturation (~95 °C), primer annealing (~55–65 °C), and extension (~72 °C).
Quantitative real-time PCR (qPCR / RT-qPCR) thermal cyclers integrate excitation optics and fluorometers above the 96- or 384-well block to monitor SYBR Green dye intercalation or TaqMan hydrolysis probe cleavage at every cycle, yielding a fractional quantification cycle (Cq / Ct).
In nucleic-acid pharmacology, RT-qPCR is the primary workhorse for measuring target mRNA knockdown potency after siRNA or antisense oligonucleotide dosing and for preparing barcoded sgRNA libraries from pooled CRISPR screens.