Protease-based droplet workflow for single-cell genomic DNA amplification and barcoding. (A) Overview of the steps in the workflow. (B) Microfluidic devices to perform the two-step droplet workflow. Cells (pseudocolored in blue) are first encapsulated with lysis buffer containing protease (yellow) and incubated to promote proteolysis (green droplets). Protease activity is then thermally inactivated, and the droplets containing the cell lysate are paired and merged with droplets containing PCR reagents and molecular barcode-carrying hydrogel beads (pseudocolored in purple).