An estimation of the volumes of the droplets generated during cell sorting

mercredi 10 août 2016
par   G. Grégori

As based on the litterature I have found, the diameter of the droplets is about 1.89 times the jet diameter. And the jet diameter is 0.866 times the nozzle orifice diameter.
You can then calculate for any nozzle orifice a proxy of the diameter of the drops, and thus its volume (assuming a drop is a sphere) : Volume = 4/3 x Pi x radius^3.
These calculations come from :

- Kachel V, Fellner-Feldegg H, Menke E. Hydrodynamic properties of flow cytometry
instruments. In : Melamed MR, Lindmo T, Mendelsohn ML, editors. Flow Cytometry
and Sorting, 2nd ed. New York : Wiley ; 1990. pp 27–44.

- KR Harkins, DW Galbraith. Factors governing the flow cytometric analysis and sorting of large biological particles. Cytometry, 8:60-70.

- Harmon DB Jr. Drop sizes from low speed jets. J Franklin Inst 1955 ;259:519–522.

We used these references in a paper dedicated to sorting long filaments (van Dijk et al., Cytometry Part A - 77A : 911-924, 2010 : http://onlinelibrary.wiley.com/doi/10.1002/cyto.a.20946/abstract).

Using these maths, here is what I get as an estimation of the drop volumes for various nozzle orifices :

Droplet volume estimation
Nozzle diametre (µm) Drop diametre (µm) Radius (µm) Drop volume (µm3) Drop volume (nl)
70 114.6 57.3 787466 0.8
85 139.1 69.6 1409920 1.4
100 163.7 81.8 2295819 2.3
150 245.5 122.8 7748390 7.7