Microfluidic Whole Genome Amplification Device for Single Cell Sequencing

We developed a microfluidic device to perform multiplex single-cell whole-genome amplification (WGA) using multiple annealing and looping-based amplification cycles (MALBAC). This device, made of polydimethylsiloxane (PDMS), allows us to monitor the whole process of cell loading and single-cell WGA for sequencing. We show that the genome coverage of MALBAC amplifications is reproducible between chambers on a single chip and between different chips, which enables data normalization using standard samples to accurately identify copy number variations (CNVs). This device provides an easy-to-operate approach to perform single cell sequencing library preparation with minimum hands-on time. It reduces the requirement of manual expertise as well as the risk of contamination, which is essential in future applications especially the medical diagnosis

Single-Cell-Based Platform for Copy Number Variation Profiling through Digital Counting of Amplified Genomic DNA Fragments

We develop a novel single-cell-based platform through digital counting of amplified genomic DNA fragments, named multifraction amplification (mfA), to detect the copy number variations (CNVs) in a single cell. Amplification is required to acquire genomic information from a single cell, while introducing unavoidable bias. Unlike prevalent methods that directly infer CNV profiles from the pattern of sequencing depth, our mfA platform denatures and separates the DNA molecules from a single cell into multiple fractions of a reaction mix before amplification. By examining the sequencing result of each fraction for a specific fragment and applying a segment-merge maximum likelihood algorithm to the calculation of copy number, we digitize the sequencing-depth-based CNV identification and thus provide a method that is less sensitive to the amplification bias. In this paper, we demonstrate a mfA platform through multiple displacement amplification (MDA) chemistry. When performing the mfA platform, the noise of MDA is reduced; therefore, the resolution of single-cell CNV identification can be improved to 100 kb. We can also determine the genomic region free of allelic drop-out with mfA platform, which is impossible for conventional single-cell amplification methods