Paper Number
PS22 

Session
Polymers in Solution

Title
Rheology of linear/circular DNA mixtures in the linear entanglement regime

Presentation Date and Time
October 16, 2018 (Tuesday) 2:45

Track / Room
Track 4 / Post Oak

Authors (Click on name to view author profile)

  1. Kong, Dejie (Texas Tech University, Department of Chemical Engineering)
  2. Banik, Sourya (Texas Tech University, Department of Chemical Engineering)
  3. San Francisco, Michael J. (Texas Tech University, Department of Biological Sciences)
  4. Robertson-Anderson, Rae M. (University of San Diego, Department of Physics and Biophysics)
  5. McKenna, Gregory B. (Texas Tech University, Department of Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Dejie Kong1, Sourya Banik1, Michael J. San Francisco2, Rae M. Robertson-Anderson3, and Gregory B. McKenna1
1Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409; 2Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409; 3Department of Physics and Biophysics, University of San Diego, San Diego, CA 92110

Speaker / Presenter 
Kong, Dejie

Text of Abstract
Circular polymers behave differently from the corresponding linear chains due to a topology difference induced by the constraints of no free chain ends. Compared to synthetic circular polymers, the polydispersity index of DNA is one and, potentially, a smaller amount of linear contamination can be achieved during the preparation of samples. Furthermore, the circular DNAs can, in principle, achieve the entangled regime more easily than synthetic polymers due to their large size which ranges from 106g/mol to 108g/mol, while the maximum size of synthetic circular polymer studied so far is 3.9x105g/mol. The circular DNA being used for this study is a fosmid [Fos45 (45kbp)] which is produced by replication of E.Coli and then extracted. In this work, the dynamic properties of entangled circular polymers mixed with similar molecular weight linear chains are studied using rheological measurements in concentrated solution. Measurements of G'(ω) and G''(ω) as well as creep and recovery are used in the characterization of nominally entangled solutions as functions of both total DNA concentrations in solution and relative amounts of linear and circular DNA. The circular Fos45 DNA is mixed with a commercially available linear lambda phage DNA (48.5kbp) at a total solution concentration of 0.5 mg/ml, 1mg/ml, and 2 mg/ml, covering a range of entanglements from approximately 7 to 51, hence they are well entangled. By varying the amount of Fos45 added to the lambda phage DNA, we examine the effects of linear polymer on the dynamic properties of circular polymers and vice versa. Future work will examine the limiting behavior of zero percent linear chains in the circular DNAs as well as circular DNA of higher molecular weight.