# Interactions Involving Neutral Surfactants and Double-Stranded DNA: The Case of Polysorbate 80 (Tween 80)

## TL;DR

This study explores how the surfactant Tween 80 interacts with DNA, revealing how it binds and compacts DNA under different conditions.

## Contribution

The study provides new insights into the single-molecule interactions of Tween 80 with DNA, both below and above the critical micelle concentration.

## Key findings

- Below the CMC, Tween 80 binds cooperatively to DNA with a high association constant.
- Above the CMC, micelles compact DNA at concentrations above 140 μM.
- The study characterizes surfactant-DNA interactions at the single-molecule level.

## Abstract

We investigate the interaction of the neutral surfactant
polysorbate
80 (Tween 80) with double-stranded DNA under nearly physiological
conditions. Single-molecule force spectroscopy assays performed with
optical tweezers were used to determine the binding mechanisms below
and above the critical micelle concentration (CMC). Below the CMC,
individual surfactant molecules bind cooperatively along the double
helix, presenting a high equilibrium association constant on the order
of 1 × 106 M–1. Above the CMC, on
the other hand, micelles can compact DNA at high concentrations (≳140
μM), opening perspectives for novel applications. The present
study advances in characterizing DNA interactions with surfactants
at the single molecule level.