Adsorption of melting deoxyribonucleic acid

TL;DR

This study numerically investigates the melting behavior of DNA near an attractive surface, revealing how adsorption influences the phase transition nature and stability of the bound state.

Contribution

It introduces a model combining DNA melting and surface adsorption, showing how surface interactions alter the phase transition from critical to first-order.

Findings

Adsorption changes the melting transition from critical to first-order.

Surface interactions significantly affect DNA stability.

Modified exponents characterize the transition with surface effects.

Abstract

The melting of a homopolymer double-stranded (ds) deoxyribonucleic acid (DNA) in the dilute limit is studied numerically in the presence of an attractive and impenetrable surface on a simple cubic lattice. The two strands of the DNA are modeled using two self-avoiding walks, capable of interacting at complementary sites, thereby mimicking the base pairing. The impenetrable surface is modeled by restricting the DNA configurations at the $z\geq 0$ plane, with attractive interactions for monomers at $z=0$. Further, we consider two variants for $z=0$ occupations by ds segments, where one or two surface interactions are counted. This consideration has significant consequences, to the extent of changing the stability of the bound phase in the adsorbed state. Interestingly, adsorption changes from critical to first-order with a modified exponent on coinciding with the melting transition. For simulations, we use the pruned and enriched Rosenbluth algorithm.