DNA diagnostics gets digitised

By Dr Mikael Kubista and Dr Anders Ståhlberg

Quantitative real-time PCR (qPCR) has during the last two decades emerged as the preferred technology for nucleic acid analysis in routine as well as in research. qPCR has the sensitivity to detect a single molecule, the specificity to differentiate targets by a single nucleotide, and, because of its exponential nature, virtually unlimited dynamic range

With the recent appearance of high throughput platforms represented by the OpenArray from Life Technologies2, the BioMark from Fluidigm3, the LC1536 from Roche4 and the SmartChip from Wafergen5, can it get better?

Well, classical qPCR is excellent platform technology and will dominate nucleic acid analyses years to come. But the exponential nature of qPCR, which is the key to its many advantages, is also limiting in some aspects. In particular, for example, multiplexing is challenging. True multiplexing based on one tube amplification and separate detection of targets is limited by competition for reagents and is in practice limited to two to four parallel reactions. In laboratories today most analyses performed are singleplex. When multiple targets are assayed the sample is divided into aliquots that are analysed separately.............