Editing Digital microfluidics (section)

==== Optical tweezers ====
[[Optical tweezers]] have also been used to separate cells in droplets. Two droplets are mixed on an electrode array, one containing the cells, and the other with nutrients or drugs. The droplets are mixed and then optical tweezers are used to move the cells to one side of the larger droplet before it is split.<ref>{{cite journal | vauthors = Neuman KC, Block SM | title = Optical trapping | journal = The Review of Scientific Instruments | volume = 75 | issue = 9 | pages = 2787–809 | date = September 2004 | pmid = 16878180 | pmc = 1523313 | doi = 10.1063/1.1785844 | bibcode = 2004RScI...75.2787N }}</ref><ref name="Shah_2009b" /> For a more detailed explanation on the underlying principles, see [[Optical tweezers]].