The development and improvement of micro- and nanotechnologies, microfluidic technologies, highly sensitive imaging systems and last advances in nanomedicine allow to creation of small-sized devices for the formation of different substances isolated droplets in the continuous liquid flow. Such droplets are kind of mini-reactors with a volume from 10 to 5 µL, surrounded by an inert medium, where different chemical reactions or other interactions can be carried out. Such reactions in small isolated volumes can be effective in various fields of researches, both at the molecular level and in the study of mammalian cells or other microorganisms. Two variants of directions related to microfluidics in the drop were considered: digital microfluidic technology allowing controlling the movement of individual drops on the substrate and droplets microfluidics allowing to form droplets in a liquid medium, to carry out various manipulations with them. Besides the different approaches to modelling of various interactions inside the lab-on a chip including different types of software packages were considered too.