Fracture of DNA in transient extensional flow. A numerical simulation study

✍ Scribed by K. D. Knudsen; M. C. López Martínez; J. Garcia de la Torre

• Publisher: Wiley (John Wiley & Sons)
• Year: 1998
• Tongue: English
• Weight: 788 KB
• Volume: 39
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/(sici)1097-0282(199609)39:3<435::aid-bip14>3.0.co;2-a

✦ Synopsis

Using the Brownian dynamics simulation technique, we studied the fracture process of' DNA chains subjected to transient extensional flow>, letting the solution with DNA molecules pass through a very small orifice (radius = 0.0065 cm), thus experiencing extensional flow ofthe convergent (sinkj type. The DNA molecules were modeled us FENE bedspring chains with the springs obeying a modijied Warner force law, as proposed by Reese and Zimm. Thefracture yield was strongly dependent on flow rate and molecular weight, reaching, in our setup, a level of 100% at aflow rate of around 0.001 cm3/s.for DNA with moleciilar weight 26 X l o 6 (T7 DNA). There wassound to exist a criticalflow rate (Qcyt,) beiow which,fracture did not occur, in accordance with what was observed in studies on polystyrene in transient extensional flow. W e found that,for DNA, the criticalflow rate depended on the molecular weight as Qo,, -M-'.4

when the hydrodynamic interaction effect (HIj was not included in the simulations. When HI was accounted,{&, the relation was,found to be Qo,, -M -' ' , close to the theoretical prediction jor,fiacture qf purtly extended chains in transient extensional flow.