Ion-induced nanopatterning of a bacterial cellulose hydrogel

TL;DR

This study demonstrates a novel ion-induced nanopatterning technique for bacterial cellulose hydrogels, enabling the creation of high aspect ratio nanostructures with potential biomedical applications.

Contribution

It introduces a plasma nanosynthesis method using argon ions to produce stable, high aspect ratio nanostructures in bacterial cellulose hydrogels with controlled size and shape.

Findings

Nanostructures are reproducible and stable to sterilization.

Pattern formation involves graphite-like carbon clusters.

Model predicts bond breaking accelerates pattern growth.

Abstract

Hydrogels provide a solution-mimicking environment for the interaction with living systems that make them desirable for various biomedical and technological applications. Because relevant biological processes in living tissues occur at the biomolecular scale, hydrogel nanopatterning can be leveraged to attain novel material properties and functionalities. However, the fabrication of high aspect ratio (HAR) nanostructures in hydrogels capable of self-standing in aqueous environments, with fine control of the size and shape distribution, remains challenging. Here, we report the synthesis of nanostructures with a HAR in bacterial cellulose (BC) hydrogel via directed plasma nanosynthesis using argon ions. The nanostructures in BC are reproducible, stable to sterilization, and liquid immersion. Using in-situ surface characterization and semi-empirical modeling, we discovered that pattern formation was linked to the formation of graphite-like clusters composed of a mixture of C-C and C=C bonds. Moreover, our model predicts that reactive species at the onset of the argon irradiation accelerate the bond breaking of weak bonds, contributing to the formation of an amorphous carbon layer and nanopattern growth.