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Updated: Jan 8, 2026
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Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
Published on: September 26, 2016
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Entropic organization of topologically modified ring polymers in spherical confinement
Kingkini Roychoudhury1,2, Shreerang Pande1, Indrakanty S Shashank1
1Indian Institute of Science Education and Research, Department of Physics, Pune 411008, India.
Physical Review. E
|December 23, 2025
Summary
Topologically modifying ring polymers with cross-links drives radial organization within spherical confinement. This entropy-driven mechanism offers insights into eukaryotic chromosome organization, distinguishing it from bacterial chromosome segregation.
Area of Science:
- Polymer Physics
- Biophysics
- Computational Biology
Background:
- Athermal ring polymers segregate in cylindrical confinement, explaining bacterial chromosome segregation.
- Eukaryotic chromosomes are confined in spherical nuclei, where ring polymers remain mixed.
Purpose of the Study:
- To propose a mechanism for driving polymer organization within spherical confinement.
- To investigate entropy-driven organization of topologically modified ring polymers.
Main Methods:
- Utilized the bead-spring model with repulsive excluded volume interactions.
- Introduced asymmetric topological modifications (cross-links) to ring polymer architecture.
- Simulated single and multiple modified ring polymers in spherical confinement.
Main Results:
- Topologically modified ring polymers exhibit emergent radial organization in spheres.
- Single polymers show peripheral localization of larger loops; multiple polymers localize smaller loops peripherally.
- Excluded volume interactions alone can yield a Flory exponent of 0.6, even with chain crossing.
Conclusions:
- Asymmetric topological modifications can drive entropy-driven polymer organization in spherical confinement.
- This mechanism may be relevant for understanding euchromatin and heterochromatin organization in eukaryotic chromosomes.
- Findings suggest a new paradigm for chromosome organization beyond simple segregation.
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