Hi, I am wondering about encapsulation of a single cell into one oil droplet. How did you achieve this?

Thank you for your question. 

Droplets are automatically generated using the Bio-Rad QX200 system (Bio-Rad) following the manufacturer’s instructions. Before you use the Bio-Rad QX200 system, you need to produce the “PCR mixture” consisted of resuspended cells at an optimal concentration, 2 × ddPCR Supermix (Bio-Rad), wild-type and mutant allele-specific TaqMan probes, primer mixtures for the target gene, and nuclease-free water for a final volume of 20 μl. An optimal concentration depends on cell types, hence you should prepare droplets of resuspended cells at various concentrations so that they include either a single cell or no cells in a droplet and confirm it on microscopy by dying nuclei of cells by Hoechst 33342. In our article, the concentrations of 2.5×10⁵/ml or 1.25×10⁵/ml were optimal. Cells were suspended by PBS. We describe below the composition of the PCR mixture for reference. 

Please read our article about sc-ddPCR “High throughput single cell analysis of mitochondrial heteroplasmy in mitochondrial diseases” in detail. (DOI: 10.1038/s41598-020-67686-z)

Sincerely,