Whether it be pathogen detection, biomarker quantification or genome editing, polymerase chain reaction (PCR) technology is being used across a multitude of the life sciences, due to its unprecedented levels of precision, accuracy and resolution. There is great interest in moving the latest iteration of this technology — droplet digital PCR (ddPCR) — from research labs to clinical settings, but it will require processes for method validation, verification and reproducibility.
A new paper published recently in Analytical Chemistry by Leonardo B. Pinheiro and colleagues at the National Measurement Institute and other Australian institutions, proved such reproducibility is possible, using Labcyte’s high precision robotic acoustic dispensing technology and a new methylated template DNA they developed.
The DNA reference material, NA008 High GC, was produced using a 96-well plate Echo® 550 liquid handler in a custom-installed Access workstation. The technology was selected, the authors note, because of its ability to deliver precise nanoliter volumes of solution without the use of tips or pins — reducing the risk of contamination or DNA loss due to adsorption — and its expression of reference value in DNA copy number amount per well, assigned by ddPCR.
“DNA reference materials in this format, in addition to verifying instrument performance, could also be used to support analytical validation of specific PCR methods,” the authors wrote.
The reference material was then shared among seven laboratories. Each received three blinded NA008 High GC reference material plates, stocks of primers, probe mix and disposables sufficient to run the assays, and were given precise instructions on how to perform ddPCR using all 96 wells of each plate.
Their conclusion: NA008 High GC was an effective reference material for quality control of ddPCR systems, consumables, instrumentation and workflow, and acoustic dispensing of DNA molecules in combination with ddPCR was instrumental in making this reproducibility possible.
“The results indicate that either single or multiple 2.5 nL aliquots can be acoustically dispensed with high precision, allowing for a flexible dispensing design format using 96-well PCR microplates,” the authors wrote.
This is great news for the future adoption and expansion of ddPCR, and we’re proud to play a part.
Learn more about how acoustic liquid handling can improve qPCR prep.