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Biomaterials

Biomaterials - Poster Session B

Poster C1 - Dual-Action Nitric Oxide and Propolis Releasing Polymeric Films for Long-Term Antibacterial Applications

Thursday, October 24, 2024
2:45 PM - 3:45 PM EST
Location: Exhibit Hall E, F & G

Introduction:  The U.S. Center for Disease Control and Prevention has stated that almost 1.7 million hospitalized patients acquire healthcare-associated infections (HCAIs) annually [1]. Bacterial infection from indwelling biomaterials contributes to HCAIs contracted by patients during hospitalization. Furthermore, antimicrobial resistance (AMR) to conventional antibiotics poses a significant challenge in treating HCAIs caused by bacteria. Nitric oxide (NO) releasing materials are an emerging solution to AMR, as NO is effective against antibiotic-resistant bacteria [2]. Various NO donors such as S-nitroso-N-acetylpenicillamine (SNAP) have been successfully incorporated into a polymer matrix for NO-releasing properties. Despite NO’s efficacy in killing bacteria, it is optimal for short-term medical devices as the reservoir of NO donor is likely to deplete after a certain period. Propolis is a bee-derived resinous bio-adhesive used medicinally for its antimicrobial and antifungal properties attributed to galangin flavonoids and hydroxycinnamic acid in its composition [3,4]. Incorporation of propolis and SNAP into a polymeric film matrix addresses the short-term application of incorporating just NO-donors and allows for better antimicrobial efficacy for a longer period of time. Previous research has established that the optimal concentration of SNAP for incorporation in polymeric films is 10% (% w/v). Additionally, 5% (% w/v) propolis was found to be the optimal concentration for maximizing the propolis release potential without interfering with physical properties of the polymer. Herein, CarboSil® (Carbosil), 10% SNAP, and 5% propolis were incorporated into polymeric films to investigate the optimal propolis concentration for best long-term NO release and antimicrobial efficacy.

Materials and

Methods:  To fabricate the four sample types, Carbosil pellets were dissolved in tetrahydrofuran to create a polymer solution. Propolis and SNAP were added accordingly to create the following sample film types: Carbosil, Carbosil + 5% propolis (5%P), Carbosil + 10% SNAP (NO), and Carbosil + 5% propolis + 10% SNAP (5%P-NO). Quantification of SNAP and propolis leaching from the sample types was determined by observing samples submerged in phosphate buffer solution (PBS) at 37°C for 28 days. Leachate from the 5%P, NO, and 5%P-NO samples collected over that 28-day period were analyzed using the UV-vis spectrophotometer. The samples were assessed for antibacterial ability using 24 h bacterial assay against Staphylococcus aureus (S. aureus). Cytocompatibility of the samples was assessed through enzymatic reduction of yellow 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to purple formazan. The MTT assay was performed on leachate collected over 24 hours against NIH 3T3 mouse fibroblasts to observe relative cell viability.

Results, Conclusions, and Discussions: The leaching study indicates that there is no effect on SNAP or propolis leaching when the two compounds are incorporated into a polymer film. The 5%P-NO film had a significant increase in bacterial reduction for planktonic and adhered bacteria when compared to Carbosil, NO, and 5%P films. 5%P-NO had a 3-log reduction for adhered bacteria and a 2-log reduction for planktonic bacteria (Figure 1). These results indicate the combination of propolis and SNAP have excellent antibacterial efficacy when combined in a polymeric film. Cell viability from the MTT assay was >80% for all sample types, indicating biocompatibility for each of the films.

Acknowledgements (Optional):  

References:
1. R.M. Klevens, J.R. Edwards, C.L. Richards, T.C. Horan, R.P. Gaynes, D.A. Pollock, D.M. Cardo, Estimating Health Care-Associated Infections and Deaths in U.S. Hospitals, 2002, Public Health Reports 122(2) (2007) 160-166.
2. F. Prestinaci, P. Pezzotti, A. Pantosti, Antimicrobial resistance: a global multifaceted phenomenon, Pathogens and Global Health 109(7) (2015) 309-318.
3. Almuhayawi MS. Propolis as a novel antibacterial agent. Saudi J Biol Sci. 2020 Nov;27(11):3079-3086. doi: 10.1016/j.sjbs.2020.09.016. Epub 2020 Sep 14. PMID: 33100868; PMCID: PMC7569119.
4. Woźniak M, Sip A, Mrówczyńska L, Broniarczyk J, Waśkiewicz A, Ratajczak I. Biological Activity and Chemical Composition of Propolis from Various Regions of Poland. Molecules. 2022 Dec 24;28(1):141. doi: 10.3390/molecules28010141. PMID: 36615334; PMCID: PMC9822435.

This material is based upon work supported by a National Science Foundation Research Experiences for Undergraduates (REU) site program under Grant No. 1950581.