||Garcia HG, Grayson P, Han L, Inamdar M, Kondev J, Nelson PC, Phillips R, Widom J, Wiggins PA. Biological consequences of tightly bent DNA: the other life of a macromolecular celebrity. Biopolymers. 2007 Feb 5 85(2):115-30.PubMed ID17103419
||Grayson P, Evilevitch A, Inamdar MM, Purohit PK, Gelbart WM, Knobler CM, Phillips R. The effect of genome length on ejection forces in bacteriophage lambda. Virology. 2006 May 10 348(2):430-6PubMed ID16469346
||osmotic pressure can be used to push on the DNA, freezing it in an equilibrium configuration where only a fraction of the DNA, from 0 to 100%, has been ejected. Though single particles are not observed with this technique, the osmotic suppression of ejection allows to effectively take a snapshot of a single moment in the ejection process. A series of such experiments was done on phage, demonstrating forces as high as 10 pN (the force corresponding to 25 atm of external osmotic pressure)
||pN=picoNewton=10^-12Newton. Since phi 29 and lambda are both packed to a similar DNA density, it is unclear whether the six fold difference in forces is caused by a difference (phi 29= 57pN, BNID 103129) between the phages or a difference in the experimental conditions.