# Bioinspired Janus Membrane with Dopamine-ZnO Coating for Antibacterial Filtration in Oral Applications

## TL;DR

A new antibacterial membrane was developed for oral use, combining dopamine and zinc oxide to reduce bacterial growth and improve filtration.

## Contribution

A novel Janus membrane with dopamine-ZnO coating is introduced for antibacterial filtration in oral applications.

## Key findings

- The membrane showed significantly reduced biofilm formation by Streptococcus mutans.
- In vivo tests in miniature pigs confirmed reduced bacterial presence on the sterile side of the membrane.
- The membrane exhibited enhanced mechanical strength and stable high filtration rates under pressure.

## Abstract

Developing an oral fibrous barrier membrane that prevents bacterial invasion while possessing antibacterial properties and facilitating fluid decompression remains a significant clinical and scientific challenge. In this study, we developed a novel Janus membrane by modifying a polypropylene (PP) fibrous membrane with dopamine and zinc oxide nanoparticles (ZnO-NPs). Fabricated via a simple floating immersion method, this asymmetric bilayer structure consists of a hydrophobic PP layer and a hydrophilic PP/dopamine@30 nm ZnO layer, providing both antibacterial properties and enhanced fluid filtration. The mechanical properties of the PP/ZnO membrane were significantly enhanced, with an increase in the Young’s modulus and ultimate tensile strength, indicating improved strength. Antibacterial activity against Streptococcus mutans (S. mutans) demonstrated a significant reduction in biofilm formation on the PP/dopamine@30 nm ZnO surface compared to unmodified PP. Water flux tests confirmed a stable, high filtration rate, with increased permeability under rising pressure. In vivo experiments with miniature pigs confirmed reduced bacterial presence on the sterile side of the membrane. These findings highlight the potential of the membrane for oral exudate filtration, extending filtration time and minimizing infection risks under strict sterility conditions. Further improvements in barrier properties are necessary to optimize its clinical performance.