R4 - Engineering dual action nitric oxide and propolis releasing polymeric matrix for extended antimicrobial efficacy

Introduction: : According to the US Center for Disease Control and Prevention, 1.7 million hospitalized patients acquire healthcare-associated infections (HCAIs) annually, which are often worsened by the prevalence of antimicrobial resistance (AMR).1 As microorganisms develop resistance, conventional antibiotics lose their effectiveness in treating infection. Thus, AMR has been identified by the Center for Disease Control (CDC) as an urgent global threat that requires immediate attention.2 Herein, the incorporation of an NO donor (SNAP) and propolis into the polymeric matrix of Carbosil facilitates the tailored release of NO and propolis to exhibit long-term antibacterial activity. The substrates were investigated for NO and propolis releasing properties in addition to their antimicrobial activity against gram positive, gram negative, and fungal strains.

Materials and

Methods: : The NO and propolis releasing substrate was obtained by blending 5% propolis and 10% SNAP into the polymeric solution of Carbosil. The change in physical property of the substrates was characterized through surface hydrophilicity and determining Young’s modulus through tensile strength. The NO release from the substrate was quantified by using a chemiluminescence Nitric Oxide Analyzer (NOA) 280i (Zysense, Frederick, CO). The propolis release was quantified by reading the absorbance of the leachate solution at different time points using a UV–vis spectrophotometer (Cary 60, Agilent Technologies). Then, fresh films as well as films subjected to physiological incubation for 7 days and 1 month were assessed for their antimicrobial ability using a 24 h bacterial assay against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Candida albicans (C. albicans). The cytocompatibility of the films was assessed using NIH 3T3 mouse fibroblast cells, while the hemocompatibility was assessed with porcine blood.

Results, Conclusions, and Discussions:: Both 10% SNAP (NO) and 10% SNAP with 5% Propolis (5%P-NO) samples showed a physiologically relevant amount of NO release for 7 days. Additionally, steady release of propolis over 28 days was observed. The combination of NO and propolis release from 5%P-NO showed 96.69%, 97.16%, and 99.93% reduction in the viability of adhered C. albicans, E. coli, and S. aureus when compared to Carbosil control. Additionally, 88.84%, 94.74%, and 99.49% reduction in the viability of planktonic C. albicans, E. coli, and S. aureus was observed with 5%P-NO samples when compared to control. The 5%P-NO sample was also able to exhibit significant reduction in viability of S. aureus after incubation in PBS for up to a month.
This work demonstrates a facile fabrication of dual-action NO and propolis-releasing polymeric substrate. The fabricated film demonstrated NO release for 7 days with steady propolis release for 28 days to extend the antibacterial lifespan of the material. The dual-action antibacterial film showed excellent antimicrobial efficacy against S. aureus, E. coli, and C. albicans. The fabricated sample also showed compatibility against fibroblast cells and blood, indicating the potential for use in blood-contacting medical devices. Hence, the current technique for the fabrication of NO and propolis releasing polymeric matrix can be extended for use in various polymeric medical devices to demonstrate antibacterial and antifungal activity without contributing towards AMR.

Acknowledgements and/or References (Optional)::

References:
(1) Klevens, R. M.; Edwards, J. R.; Richards, C. L.; Horan, T. C.; Gaynes, R. P.; Pollock, D. A.; Cardo, D. M. Estimating Health Care-Associated Infections and Deaths in U.S. Hospitals, 2002. Public Health Reports 2007, 122 (2), 160-166. DOI: 10.1177/003335490712200205 (acccessed 2023-12-06T22:36:27).
(2) Prestinaci, F.; Pezzotti, P.; Pantosti, A. Antimicrobial resistance: a global multifaceted phenomenon. Pathogens and Global Health 2015, 109 (7), 309-318. DOI: 10.1179/2047773215y.0000000030 (acccessed 2023-12-06T22:47:47).