Introduction: Oral polymicrobial biofilm formation occurs as a result of the synergistic interaction of fungal (e.g., Candida albicans) and bacterial pathogens (e.g., Staphylococcus aureus) and has been reported to cause severe dental caries and periodontal diseases. One of the promising ways of combating biofilms is the use of nanoparticles (NPs) manufactured utilizing green chemistry. The present study aimed to synthesize gold NPs using fucoidan, β-caryophyllene, and phloroglucinol to control oral polymicrobial biofilms caused by S. aureus and C. albicans.
Methods: Fucoidan–gold nanoparticles (Fu-AuNPs), β-caryophyllene–gold nanoparticles (β-c-AuNPs), and phloroglucinol–gold nanoparticles (PG-AuNPs) were synthesized using natural molecules. These NPs were characterized using UV-vis absorption spectroscopy, FTIR, FE-TEM, EDS, DLS, zeta potential, and XRD. The colony counting method was employed to check the antibiofilm effects of these NPs towards polymicrobial biofilms of S. aureus and C. albicans.
Results: The synthesized Fu-AuNPs, β-c-AuNPs, and PG-AuNPs were found to be spherical in morphology, with sizes of 75.66 ± 9.28 nm, 17.6 ± 1.2 nm, and 46.71 ± 6.40 nm, respectively. The minimal inhibitory concentration (MIC) of Fu-AuNPs, β-c-AuNPs, and PG-AuNPs against S. aureus and C. albicans was determined to be 1024 μg/mL, 512 μg/mL, and 2048 μg/mL, respectively. The inhibition of polymicrobial biofilms of S. aureus and C. albicans by these NPs was significant at the sub-MIC level and was concentration-dependent. In addition, Fu-AuNPs, β-c-AuNPs, and PG-AuNPs at MIC and above MIC significantly eradicated mature polymicrobial biofilm.
Conclusions: This study demonstrated that Fu-AuNPs, β-c-AuNPs, and PG-AuNPs act as an alternative strategy to control oral pathogens by inhibiting the initial stage of biofilm formation and eradicating mature polymicrobial biofilms of S. aureus and C. albicans.
Funding: This research was supported by the Basic Science Research Program through a National Research Foundation of Korea grant funded by the Ministry of Education (RS-2023-00241461) and Research Grant of Pukyong National University in 2024 (202416570001).
