Figure 4.

Examples of microfluidic screening systems. (i) Picolitre-scale droplets encapsulating cells expressing a particular enzyme variant that are lysed and screened for fluorescence using a reporter for the enzymatic process¹¹⁹. Microfluidic systems can also sort eukaryotic cells by their mechanical and electrical properties, for example (ii) their stiffness (adapted with permission from ¹²⁹, copyright 2017 Nature Publishing Group), (iii) electrical conductivity (adapted with permission from ¹³¹, copyright 2009 American Chemical Society), or compressibility (adapted with permission from ¹²⁸, copyright 2014 National Academy of Sciences).