Use of Droplet PCR in Biomedical Research

Abstract

With the development of semiquantitative PCR, scientists were able to begin looking at specific genes; however, this technique had several limitations. Specifically, semiquantitative PCR is an end point study, only yielding information on the expression of the target gene at the end of several amplification cycles, which, in turn, limits its ability to quantify gene expression based only on signal intensity. This signal could be affected by various factors, such as the number of cycles performed, and often the final product is oversaturated. In order to combat this limitation, scientists developed real-time PCR (qRT-PCR). qRT-PCR allowed for a “real time” view of gene expression by taking a reading after each individual amplification cycle. With these successive readings, qRT-PCR allows for a relative quantification of gene expression between an experimental group and its control using the “double delta” (2Δ equation). However, quantitative PCR has its own limitations. To address these limitations, a process known as digital droplet PCR (ddPCR) was developed. In this chapter readers would learn about the ddPCR technique and its applications.