# Breaking of the Up‐Down Symmetry of DNA Origami on a Solid Substrate

## TL;DR

This paper introduces a simple method to control the orientation of DNA origami nanostructures on a surface by adjusting magnesium ion concentration, achieving perfect alignment.

## Contribution

A straightforward method to achieve 100% S orientation of chiral double-L DNA origami on mica by tuning Mg2⁺ concentration.

## Key findings

- Tuning Mg2⁺ concentration controls the adsorption orientation of CDL DNA origami on mica.
- Global shape distortions enable 100% S orientation of CDL DNA origami.
- Orientation is influenced by ionic environments and nanostructure conformation.

## Abstract

Controlling the surface orientation of DNA origami nanostructures (DON) is crucial for applications in nanotechnology and materials science. While previous work utilized various DON modifications, simple methods for controlling their landing orientation remain scarce. Here, we demonstrate a straightforward approach to control the adsorption orientation of chiral double‐L (CDL) DON on mica by tuning magnesium ion (Mg2⁺) concentration and exploiting global shape distortions. Using atomic force microscopy (AFM), we analyzed the resulting distribution of the mirror‐image orientations, referred to as S and Z orientations, at both buffer/mica and air/mica interfaces and identified conditions resulting in homogenous CDL orientation of 100% S. These results demonstrate how DON conformation and ionic environments influence DON orientation, offering insights for precise nanostructure deposition.

In this study, the surface orientation of chiral double‐L (CDL) DNA origami on mica was controlled by tuning magnesium ion (Mg2⁺) concentration. This simple yet powerful method, exploiting global shape distortions, achieved 100% S orientation enabling precise nanostructure deposition.