Introduction: Excessive immune response and development of bacterial infections are two major problems accompanying organ replacement and implant surgeries. Our group aims to develop bioactive coatings to address these issues. Poly(arginine) and hyaluronic acid (PAR/HA) layer-by-layer films are supramolecular thin films (thickness about 1µm) that are easy to build, with promising immunomodulatory and antimicrobial properties 1-4. Here, we investigated the film behavior on CAVI-T intranasal balloon. CAVI-T (Dianosic, France) is a CE-marked medical device which addresses the treatment of intranasal bleeding and which can be used after nasal reconstruction. The device is composed of an inflatable balloon made of polyurethane used for compression of the nasal cavity. A feasibility study was performed with (PAR/HA) film onto polyurethane, looking for film characterization and its antimicrobial activity once deposited onto the balloon, after sterilization, storage and balloon handling, including balloon inflation. As an inflatable medical device CAVI-T is a good testing bed for the modification of mechanically active biomaterial structures.
Methodology: To construct (PAR/HA) multilayer films, polyurethane was alternatively dipped in PAR and HA solutions with intermittent rinsing steps. Coating construction on the substrate was characterized through observation by fluorescence microscopy after film staining with fluorescein isothiocyanate-conjugated PAR. For antimicrobial assays, coated polyurethane was incubated with a Staphylococcus aureus suspension for 24 hours. Planktonic bacteria were quantified by OD600nm measurement in the supernatant. Adherent bacteria were observed at the polyurethane surface after a fluorescent staining of healthy bacteria. Antimicrobial assays were repeated on the device after ethylene oxide sterilization, after accelerated aging and after 10 cycles of inflation/deflation of the balloon.
Results: The best coating construction parameters were defined according to the film homogeneity and thickness. (PAR/HA) films deposited onto polyurethane show a strong bactericidal activity. No bacteria were detected into the supernatant or at the polyurethane surface after 24 hours of contact. After the coating of the device and its sterilization, the antimicrobial activity of the (PAR/HA) remained unchanged. Same results were obtained after an accelerated aging. A final set of experiments was launched after inflation and deflation of the balloon performed into a test tube to mimic the contact with the intranasal cavity during the device introduction. Once again, the antimicrobial activity remained the same.
Conclusion and discussion: These results show the capacity of (PAR/HA) films to ensure antimicrobial activity when coated on the polyurethane balloon of CAVI-T device. (PAR/HA) coating appears to be a simple and powerful system, compatible with an utilization in polyurethane based scaffolds and medical devices. Next step of this study will be the evaluation of the coating for its ability of promoting healing in the specific case of intranasal bleeding. Immunomodulatory and hemostatic properties of the film will be assessed. Thus, the coating design could be tuned to fit polyurethane based scaffolds and devices specific needs.
References: 1 Özçelik et al., Adv. Healthc. Mater. 4, 2026-2036 (2015). 2 Mutschler at al., Chem. Mater. 28, 8700-8709 (2016). 3 Mutschler et al., Chem. Matter. 29, 3195-3201 (2017). 4 Patent WO2017191110A1 - EP3241570A1