Radius-dependent phase behavior: Giant DNA and alginate in a cell sized sphere

We study the phase behavior when a mixture of two semi-flexible polymers, giant DNA and alginate, is highly confined mixture in a cell-sized scale space. The characteristic lengths of giant DNA is different from those of alginate. Through the microscopic observation, we found that the volume/surface area ration and the higher-order structure of giant semi-flexible polymer are the crucial determinants of the phase behavior in cell-sized scale space. When the volume/surface area ration is ≤ 1.0 under the osmotic pressure which is caused by the smaller polymer is small, the larger polymer can be depleted on the surface. When the volume/surface area ration is ≤ 1.0 with the higher osmotic pressure which is caused by the smaller polymer, the depletion of the larger polymer on the surface causes the phase-separation between two polymers within the space. When the volume/surface area ration is > 1.0 with higher osmotic pressure, the elongation force of the meta-stable coil becomes the dominant factor to decide the phase behavior in a cell-sized scale space.