Nonmonotonic DNA-length-dependent mobility in pluronic gels

Area of Science:

• Polymer Science
• Biophysics
• Physical Chemistry

Background:

• Traditional gel electrophoresis separates DNA fragments based on size, with mobility decreasing monotonically with length.
• Pluronic block copolymers form micellar gels with unique properties that can influence molecular transport.
• Understanding DNA mobility in complex fluids is crucial for developing advanced separation techniques.

Purpose of the Study:

• To investigate the size-dependent mobility of DNA fragments in pluronic F127 and P123 micellar gels.
• To elucidate the mechanisms governing DNA migration in these non-traditional gel matrices.
• To compare DNA mobility in pluronic gels with that in conventional agarose gels.

Main Methods:

• Two-dimensional electrophoresis was employed to separate DNA fragments (20-3500 base pairs) in both agarose and pluronic gels.
• Brownian dynamics simulations were utilized to model DNA mobility and hydrodynamic interactions within pluronic lattices.
• Molecular dynamics simulations with explicit micelle coronas were performed for pluronic F127 to investigate interaction details.

Main Results:

• DNA mobility in pluronic gels exhibited non-monotonic behavior with fragment length, contrasting with the monotonic decrease in agarose gels.
• The observed mobility variations correlated strongly with the diameter of the spherical micelles in the pluronic gels.
• Brownian dynamics simulations successfully reproduced the rising, falling, and oscillatory trends in DNA mobility.

Conclusions:

• The complex, non-monotonic DNA mobility in pluronic gels is influenced by micellar structures and hydrodynamic interactions.
• Hydrodynamic interactions mediated by the hydrated poly(ethylene oxide) corona of micelles likely contribute to the initial rise in mobility with DNA length.
• These findings offer insights into DNA behavior in complex fluids and potential applications in separation science.