Digital microfluidics, enabling entrapping of living cells inside of the emulsion droplets, is an attractive platform for rapid single-cell analysis. Here we present a simple way for encapsulating and observing the viability and growth kinetics of single paramecia cells in droplets (approx. 200 nL). The aim of the work is to measure the viability of single cells within hundreds of microreactors, exposed to different silver nitrate concentrations. Hundreds of droplets were created which were containing paramecia cells, culture media, viability indicator resazurin and silver nitrate. Detection of the cells activity was done by measuring the fluorescence intensity of the viability indicator, added to each droplet. To be flexible with different viability indicators, the spectrum of every single droplet was measured in less than one minute. With the help of the spectra counting and labelling of the droplet was also achieved. Finally, our detection platform enabled precise determination of a number of encapsulated cells per droplet relying only on metabolic activity of the paramecia cell.