# Essential Oil Blends or Their Component Blends as Antimicrobial Compounds of Polysaccharide Coatings on Metallic Biomaterials

## TL;DR

This study explores how essential oils and their compounds can be embedded in polysaccharide coatings on metal surfaces to create antibacterial materials, finding that alginate coatings are highly effective against bacteria but also more toxic to cells.

## Contribution

The work introduces a novel approach to developing antibacterial surfaces using essential oil compounds in combination with polysaccharide matrices, highlighting differences in performance and compatibility based on the matrix used.

## Key findings

- Alginate-based coatings showed high antibacterial activity against S. aureus but also increased cytotoxicity.
- Chitosan-based coatings provided better cytocompatibility while maintaining antibacterial properties.
- The structure and distribution of additives in the coatings significantly influenced their performance.

## Abstract

What are the main findings?
influence of polysaccharide matrix and substrate on EPD process and coatings properties;alginate coatings showed superior antibacterial and anti-biofilm activity;alginate and chitosan coatings differed in droplet size and additive distribution;interactions between oils, active compounds, and polymer matrices were observed;alginate-based coatings showed high activity against S. aureus, but also cytotoxicity.

influence of polysaccharide matrix and substrate on EPD process and coatings properties;

alginate coatings showed superior antibacterial and anti-biofilm activity;

alginate and chitosan coatings differed in droplet size and additive distribution;

interactions between oils, active compounds, and polymer matrices were observed;

alginate-based coatings showed high activity against S. aureus, but also cytotoxicity.

What are the implications of the main findings?
both polymers enable multi-component loading but require improved coating stability;control of droplet size and distribution is critical for coating performance;optimization of plant-derived compound type and concentration is required.

both polymers enable multi-component loading but require improved coating stability;

control of droplet size and distribution is critical for coating performance;

optimization of plant-derived compound type and concentration is required.

The work provides novel insight into the development of advanced antibacterial surfaces using the combination of essential oils, cinnamon oil, thyme oil, and tea tree oil, as well as their active compounds, including cinnamaldehyde, thymol, and terpinene-4-ol, embedded in the chitosan and sodium alginate matrix. All coatings obtained in a two-stage electrophoretic deposition process on stainless steel and titanium substrates were characterized by high adhesion strength. The microstructural differences between the coatings were mainly related to the size and location of the additives. Structural investigation showed the impact of individual oil components on intermolecular bonds between polysaccharide chains and the formation of molecular interactions in a specific spatial conformation. The surface of all coatings was minimally rough and had a hydrophilic character. A clear matrix-dependent trade-off between antibacterial efficacy and cytocompatibility was observed: alginate-based coatings achieved strong anti-Staphylococcus aureus activity (2.81 log CFU/mL) at the expense of increased cytotoxicity, while chitosan-based systems provided a more favorable cytocompatibility profile, maintaining cell viability above 70% for selected formulations. This work provides insight into the development of natural antibacterial surfaces by the combination of active compounds and shows the distinctions on many levels between the coatings with various polysaccharide matrices.