# Biofilm Control with Rare-Earth Oxides: A Mechanistic Framework for Next-Generation Antibiofilm Materials

## TL;DR

Rare-earth oxides can disrupt biofilms through matrix-level mechanisms, offering a new approach to managing infections and improving healing outcomes.

## Contribution

This paper provides a unified framework for understanding and designing rare-earth oxide materials to control biofilms.

## Key findings

- Biofilm control by rare-earth oxides occurs through EPS destabilization and eDNA sequestration, not bactericidal action.
- Cerium oxide is a benchmark due to its redox adaptability and catalytic activity.
- Non-ceria rare-earth oxides require functionalization to achieve antibiofilm effects.

## Abstract

Biofilm-associated infections remain a major barrier to wound healing, implant integration, and chronic infection management. Rare-earth oxides (REOs) have emerged as promising antibiofilm materials, though their mechanisms, limitations, and translational potential are still being defined. Cerium oxide (CeO2) serves as the benchmark due to its redox adaptability, oxygen-vacancy-driven catalytic activity, and host compatibility. In contrast, non-ceria REOs show antibiofilm effects under more restricted conditions, often requiring surface functionalization, composite architectures, or hybrid organic–inorganic interfaces—such as polyphenol coatings or hydroxyapatite-based composites—to achieve comparable activity. Across systems, biofilm control arises not from bactericidal potency but from matrix-level mechanisms including extracellular polymeric substance (EPS) destabilization, extracellular DNA (eDNA) sequestration, redox modulation, and quorum-sensing interference. Preclinical and near-clinical evidence, particularly in chronic wound models, supports the translational relevance of these mechanisms, though the evidence base remains preliminary. This review synthesizes mechanistic data across cerium-, samarium-, lanthanum-, and strontium-based systems to establish a unified framework for REO-mediated biofilm disruption. REOs are positioned as biofilm-modulating platforms that complement antibiotics, enhance healing, and improve outcomes. Design rules emphasize controlled redox activity, targeted coordination chemistry, functional surface engineering, and host-compatible performance, alongside regulatory and manufacturing guidance for future development.