Publications

We performed a theoretical study on the nature of the collapsing, or folding, transition of polyelectrolyte chains entrapped in a narrow closed space, as a model of living cells enclosing giant DNA chains. We adopted a theoretical treatment with a mean-field approximation by taking into account the effect of the translational entropy of small ions. For a system with two, long (L) and short (S), chains trapped in a narrow space, we found that, with an increase in the concentration of an added trivalent cation, Pi, the S chain collapses first while the L chain remains an elongated coil. With increased P+, the L chain collapses while the S chain decollapses. Finally, with an excess of P+, both the S and L chains collapse. It may be worth examining such theoretical expectations by actual experiments.