Updated on 24 October 2013
Workflow of digital PCR involves three steps of sample partitioning, chain reaction and data analysis. The partitioning is done on tube chip without the need for a dedicated instrument or multiple pipetting steps thereby minimizing sample contamination and error. It enables enhanced performance over traditional PCR methods and allows simultaneous processing of multiple chips, thereby saving time, cost and efficiency.
He explains, "Digital PCR comprises of three key steps. First, the sample is partitioned into smaller sub-reactions. Once the partition is done, the sub-reactions undergo amplification similar to a typical PCR process. After amplification, the sub-reactions are interrogated to determine if they are positive or negative for PCR products. Due to the new technology of digital PCR of partitioning the sample in a way that only a single copy of DNA is present in each sub-reaction, the method is more sensitive and precise than a standard a PCR."
Dr Ng mentions that his digital PCR could play an extremely important role in serious disease diagnostics like cancer and detection of rare mutations.
"Detection of rare mutations by a standard PCR is often challenging due to the presence of a large amount of normal DNA in the sample. In digital PCR, the DNA sample is partitioned so that only at most one copy is present in each sub-reaction and the presence of rare mutation are not masked by an overabundance of normal DNA in the background. Therefore, digital PCR provides unprecedented sensitivity for the detection of rare mutations or occurrences," Dr Ng explains.
Digital PCRs finds application in cancer diagnostics for analysis of circulating tumor DNA to monitor metastatic breast cancer, detection of expression levels of colorectal cancer-related genes, quantifying HER2 expression in breast cancer and analyzing lung cancer genome. Digital PCRs is also applicable to prenatal diagnostics for molecular detection of fetal chromosomal, detection of cell-free fetal DNA in maternal plasma and non-invasive diagnosis of hemophilia. It is also applied for detection of multidrug resistance of tuberculosis measurement of HIV DNA.
An entrepreneurial move
Dr Ng shares that being a researcher he initially lacked the acumen of an entrepreneur but his experience in the involvement of starting up a medtech company in Singapore exposed him to learn the tricks of the trade. Owning a sound technology of a digital PCR, Dr. Ng was awarded SPRING Singapore's Technology Enterprise Commercialization Scheme (TECS) Proof-of-Concept grant has successfully got two rounds of funding of around $250,000 and $500000.