Development of drug-loaded MnO2 nanoflowers on nitric oxide-releasing polymer platforms for antimicrobial and antifungal applications.

The integration of small molecules into medical devices offers a promising strategy for mitigating clinical complications. Specifically, nitric oxide (NO), a bioavailable small molecule, can be incorporated into medical devices to enhance their antimicrobial and antithrombotic properties. However, the combination of these platforms has targeted bactericidal effects with limited antifungal properties. In this work, a manganese dioxide (MnO2) nanoflower is combined with an NO-releasing, clinically relevant polymer. Due to the nanoflower's porosity, Amphotericin B (AmB) is loaded, yielding a multifunctional medical substrate with a unique morphology and crystal structure that imparts a 'flower' shape, making it an efficient drug-loading vehicle. These coated particles serve as multifunctional platforms for NO catalysis, enhancing antibacterial, antifungal, and cytocompatibility properties. The designed material platforms combine an NO-releasing polyurethane (PU) coated with AmB-loaded MnO2 nanoflowers (M-AmB), yielding PU NO-releasing M-AmB platforms, and were successfully synthesized and characterized through various analytical methods. The fabricated material exhibits catalyzed NO release from the surface in physiological environments. The PU NO-releasing M-AmB materials display enhanced antimicrobial (98.5% vs. C. albicans, and > 95% vs. E. coli and S. aureus) and antibiofilm properties at 24 and 72 h, respectively. The studies explore multi-species interactions involved in infection and examine the clinical challenges associated with medical device implantation.