Digital PCR (polymerase chain reaction) allows scientists to find a needle in a haystack; the DNA sample can be quantified very accurately and targets that only differ from the wild-type by one base pair can be detected. One such 'needle' would be the rare somatic cell mutation that indicates the onset of cancer.
"The digital array is truly an enabling technology that could spawn new fields of science," said Gajus Worthington, Fluidigm's chief executive.
PCR was invented in the 1980s as a technique for replicating a small amount of DNA many times over, without the use of a living organism.
Scientists can search the copied DNA for specific genes, for example mutants and therefore diagnose diseases such as cancer. However, DNA sequence variations that only occur at very low levels can be very difficult to spot with the comparatively insensitive traditional PCR that amplifies a pool of DNA templates.
It is also impractical to attempt to quantify normal PCR methods because of the thousands of pipetting steps and associated errors.
The BioMark technology produced by Fluidigm divides 12 sample mixtures into 765 different wells, effectively enriching the sample by this factor. The subsequent amplification of a single template makes subtle differences in sequence much more easy to detect.
Further applications of the technology are made possible by being able to quantify the DNA sample. By varying the amount of sample, the number of wells filled changes. In this way, it is possible to extrapolate the number of copies in each well. Absolute quantification is possible because only the wells containing sample produce a signal.
This technique could, for example, be used to examine how the amount of virus (such as, AIDS) in a patient's blood stream responds to different treatments.