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

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.