# Antifouling Polymer-Coated Anthocyanin-Loaded Cellulose Nanocrystals Demonstrate Reduced Bacterial Detection Capabilities

## TL;DR

This study creates antifouling materials that change color when bacteria are present, using polymer-coated cellulose nanocrystals loaded with anthocyanin dye.

## Contribution

The novelty lies in combining antifouling polymers with anthocyanin-loaded cellulose nanocrystals to create color-changing materials for bacterial detection.

## Key findings

- Anthocyanin-loaded CNCs showed vibrant color changes in response to bacterial contamination.
- Polymer-coated CNCs had limited color change in dried film form due to improved antifouling properties.
- SP-RAFT polymerization successfully grafted B5AMA polymers onto CNC surfaces.

## Abstract

Microbial contamination is a global concern with impacts on a variety of industries ranging from marine to biomedical applications. Recent research on hydrophilic polymer-based coatings is focused on combining antifouling polymers with nanomaterials to enhance mechanical, optical, and stimuli-responsive properties, yielding colour changing, self-healing, and super hydrophilic materials. This study combines the hydrophilic and antifouling properties of vitamin B5 analogous methacrylamide (B5AMA)-based polymers with stimuli-responsive anthocyanin-dye-loaded cellulose nanocrystals (CNCs) to develop antifouling materials with colour changing capabilities upon bacterial contamination. Poly(B5AMA)-grafted CNCs were prepared through surface-initiated photoiniferter reversible addition fragmentation chain transfer (SP-RAFT) polymerization and characterized through proton nuclear magnetic resonance (1H-NMR), transmission electron microscopy (SEM/TEM), and X-ray photon spectroscopy (XPS) to confirm the formation of surface-grafted polymer chains. The bare CNCs and poly(B5AMA)-grafted CNCs were loaded with anthocyanin dye and evaluated for pH-dependent colour changing capabilities. Interestingly, anthocyanin-loaded CNCs demonstrated vibrant colour changes in both solution and dried film form upon bacterial contamination; however, limited colour changing capabilities of the composites, specifically in dried film form, were attributed to the enhanced dispersibility and antifouling capabilities of the polymer-coated CNCs.