A recent study published in Advanced Materials Interfaces presents a bio-based nanocomposite coating designed to reduce the risk of catheter-associated urinary tract infections (CAUTIs) in commercial silicone catheters.
The coating integrates bactericidal, antibiofilm, and antioxidant properties. It is applied using a nanoparticle–ultrasound-assisted method to improve the performance of indwelling medical devices.
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Background
Preventing biofilm formation on urinary catheters remains a key challenge in managing CAUTIs. Conventional strategies, often reliant on antibiotics or antiseptics, carry the risk of promoting microbial resistance and cytotoxicity.
Recent developments in nanostructured coatings, particularly those applied using ultrasound-assisted techniques, have shown the potential to extend the infection-free lifespan of silicone-based catheters. This study builds on those advances by employing biodegradable and bioactive materials to improve surface functionality while minimizing adverse biological effects.
Citronellal, a natural compound with known antibacterial and antioxidant activity, was selected as the active agent, encapsulated within nanoparticles to enhance its stability and control its release. The use of chitosan as the coating matrix supports biocompatibility and aligns with broader efforts to incorporate sustainable materials in biomedical applications.
Experimental Approach
The researchers prepared CLG_NPs by dissolving lauryl gallate and citronellal in ethanol, followed by sonication with Tween 80 to produce a stable dispersion.
This dispersion was then applied to commercial silicone catheters via a sonochemical coating process, which facilitates the uniform embedding of nanoparticles into polymer matrices under relatively mild conditions.
The coated catheters were evaluated using microbiological, biochemical, and biocompatibility assays. Antimicrobial performance was assessed in a dynamic in vitro model simulating the human bladder environment. In this setup, both coated and uncoated catheters were exposed to a bacterial inoculum and flushed continuously with sterile artificial urine over seven days.
Biofilm formation was quantified using crystal violet staining. Biocompatibility was tested using human fibroblast and keratinocyte cells to determine the coating’s cytotoxic potential.
Results and Analysis
The CS/CLG_NPs coating showed significant antibacterial activity against Escherichia coli and Staphylococcus aureus, two common CAUTI pathogens.
Biofilm formation was substantially reduced on coated catheters compared to uncoated controls, particularly under flow conditions that mimic urinary excretion. The coating retained its effectiveness throughout the seven-day testing period, indicating both strong adhesion to the catheter surface and sustained antimicrobial activity.
In addition to its bactericidal effects, the coating exhibited measurable antioxidant properties, which are relevant in mitigating oxidative stress linked to bacterial metabolism and inflammatory responses. Notably, the release of citronellal from the coating was found to be pH-dependent, a feature that could enable more responsive antimicrobial activity in fluctuating physiological conditions.
The study also emphasized the importance of biocompatibility. In vitro assays confirmed that the hybrid coating did not adversely affect the viability or morphology of human skin-derived cells. This supports its suitability for clinical applications requiring extended contact with human tissue.
Conclusion
This study outlines the development of a multifunctional nanocomposite coating that addresses both microbial colonization and oxidative stress on urinary catheters.
Through a waterborne, ultrasound-assisted process, researchers successfully embedded CLG_NPs into a chitosan matrix, resulting in a coating with antimicrobial, antibiofilm, and antioxidant functionalities. The coating demonstrated stability, controlled release behavior, and biocompatibility in vitro, indicating its potential for integration into catheter-based devices.
Further work is needed to assess long-term in vivo performance and to optimize coating parameters for clinical deployment. However, these findings contribute to the growing body of research focused on functionalizing medical device surfaces to improve patient outcomes and reduce infection-related complications.
Journal Reference
Puertas-Segura A., et al. (2025). Durable Bio-Based Nanocomposite Coating on Urinary Catheters Prevents Early-Stage CAUTI-Associated Pathogenicity. Advanced Materials Interfaces. DOI: 10.1002/admi.202401016, https://advanced.onlinelibrary.wiley.com/doi/10.1002/admi.202401016