The basic principle of droplet microfluidics is easy to appreciate: highly monodisperse aqueous droplets are generated in an inert carrier oil in microfluidic channels on a chip and each droplet functions as an independent microreactor. Hence, each droplet is the functional equivalent of a well (or tube), yet the volume of droplet is roughly a thousand to a million times smaller. Such massive reduction in reaction volume provides huge savings in reagents cost when performing large numbers of reactions in parallel. Furthermore, unlike the conventional microtiter plates or valve-based microfluidics, droplets are intrinsically scalable: the number of reaction ‘wells’ is not limited by the physical dimensions of the chip but scales linearly with the emulsion volume. Different microfluidic modules can be employed to manipulate droplets in sophisticated, yet highly controllable manner. Large numbers of droplets (>10^9) can be generated at astonishingly high rates (>20,000 droplets per second), their size tuned precisely, new reagents introduced into pre-formed droplets at defined time points, droplet split and sorted, therefore opening new opportunities for single-cell -omics field. Many useful microfluidic techniques have been developed to profile and even selectively purify single-cells, however, the demand for methods with better analytical performance and improved high-throughput capabilities, remains very high. We are working at fulfilling this demand by bringing higher throughput, reduced reagent cost, scalability and single-molecule resolution for diverse set of quantitative experiments in cell biology and biomedicine.