Abstract:
In this report, we present a theory to understand the effects of osmotic pressure due to neutral macromolecular crowders on double-stranded DNA or any semiflexible polymer under tension. The leading order effect is a crowder-induced compaction, which acts against the external applied force. This compacting force f∗ is dependent upon crowder size r and volume fraction ϕ, high ϕ and small r result in a higher compaction force f∗. At first order in perturbation theory, we calculate a fluctuation-dependent correction to the depletion volume, which competes with the compaction of the polymer for large crowders leading to expansion of the polymer.
