# Chiral Hierarchies at the Nanoscale Revealed by Three-Dimensional Scanning Electron Diffraction

## TL;DR

This paper introduces a new method using scanning electron diffraction to map the 3D chiral structure of nanoscale materials like cellulose in plant cell walls.

## Contribution

A novel 3D reconstruction method using low-dose scanning electron diffraction for resolving chiral nanoscale structures in beam-sensitive materials.

## Key findings

- The method resolved 3D cellulose fibril orientation in native oat husk and birch wood with sub-100 nm resolution.
- A multilayered cell wall architecture with alternating helical handedness was revealed.
- The technique enables rapid analysis of complex hierarchical structures using widely available instrumentation.

## Abstract

Natural biocomposites such as wood and plant cell walls
exhibit
prominent mechanical properties largely attributed to the nanoscale
organization of fibrous components, such as cellulose, which often
adopt chiral arrangements. However, resolving the three-dimensional
(3D) arrangement of these structures at the nanoscale remains a significant
challenge, particularly in beam-sensitive materials. This study introduces
a method for 3D reconstruction of orientation based on scanning electron
diffraction (SED), enabling the quantitative mapping of chiral supramolecular
organization with sub-100 nm spatial resolution. By acquiring low-dose
SED data at multiple tilt angles and applying a symmetry-based reconstruction
algorithm, we resolved the 3D orientation of cellulose fibrils in
native oat husk and birch wood. Our results reveal a multilayered
cell wall architecture with alternating helical handedness, providing
precise measurements of 3D fibril orientation. This method reveals
complex hierarchical structures at the nanoscale, enabling rapid data
acquisition and analysis using widely available instrumentation. The
ability to resolve such chiral organization provides insights into
material properties as well as opportunities for designing bioinspired
materials with tunable mechanical and functional properties that extend
far beyond natural biocomposite materials.