Prof. Rudi Podgornik "Size-dependent forced PEG partitioning into channels"

Colloidal model systems allow for a flexible tuning of particle sizes, particle spacing and mutual interactions at constant temperature. Colloidal suspensions typically crystallize as soon as the interactions get sufficiently strong and long-ranged. Several strategies have been successfully applied to avoid Osmotic stress is used to push a DNA molecule into the viral capsid by the action of PEG in solution. I will analyze a variation on this problem with a simple model of a binary polymer mixture and find that polymer size dependent partitioning into a nanopore also has a complex dependence on the composition of the polymer mixture and the nanopore­ penetration penalty. For a polydisperse polymer solution of big and small polymer chains (bPEG and sPEG, respectively), PEG3400 and PEG200, only the sPEG is allowed to enter the pore. The calculated partition coefficient will be compared with measured size-dependent forced PEG partitioning into channels: VDAC, OmpC, and Alpha-Hemolysin. The interpretation is based on the idea that relatively less penetrating polymers push the more easily penetrating ones into nanosize channels in excess of their bath concentration. Comparison of the theory with experiments is excellent for VDAC.

invited by Jan Behrends