# Water-Resistant Antibacterial Coatings Using Cetylpyridinium Chloride - Graphene Oxide Composites

## TL;DR

This paper introduces a durable antibacterial coating made from cetylpyridinium chloride and graphene oxide that remains effective even after multiple washings.

## Contribution

A novel CPC–GO composite is developed for long-lasting antibacterial coatings suitable for medical applications.

## Key findings

- CPC–GO composites showed stable antibacterial activity after multiple washes.
- Structural analysis confirmed the formation of a planar CPC–GO composite via ionic bonds.
- The composite is promising for use in medical devices where disinfection is difficult.

## Abstract

Hospital-acquired infections remain a persistent threat
in healthcare
settings, especially with the increasing number of elderly and immunocompromised
patients. In situations where the use of disposable materials is difficult,
durable antibacterial surface coatings are essential. In this study,
we report the structural characterization of cetylpyridinium chloride-graphene
oxide (CPC–GO) hybrid materials and the sustainability of their
antibacterial effects, aiming at washable antibacterial coatings for
medical applications. Graphene oxide (GO) has a large surface area
and numerous functional groups, while cetylpyridinium chloride (CPC)
is a quaternary ammonium compound with well-documented antibacterial
activity. We hypothesized that the stable incorporation of CPC through
the functional groups of GO could improve surface retention and provide
long-term antibacterial performance. The structural properties of
the CPC–GO composites were characterized by UV–vis spectroscopy,
X-ray diffraction, thermogravimetric analysis, scanning electron microscopy,
and atomic force microscopy. These analyses confirmed the formation
of a complex through ionic bonds and the maintenance of a planar composite
structure. The antibacterial performance of the CPC–GO coatings
was examined using representative bacteria. Notably, the CPC–GO
coatings maintained their antibacterial activity significantly better
than the negative controls even after multiple washings. The excellent
surface retention of the CPC–GO composite suggests its potential
as a next-generation antibacterial coating for areas where disinfection
and sterilization are impossible, such as the interior of complex
medical devices. This study suggests a strategy to extend the efficacy
of existing antibacterial agents through the application of nanomaterials.
Future studies will focus on the controlled release, long-term stability,
and biocompatibility of CPC to realize clinical applications.