Nanoencapsulation of Mānuka Oil and β-Triketones for Antimicrobial Delivery in Oral Wounds

Abstract

OBJECTIVES: Bacterial invasion of periodontal tissues is a common oral health concern, highlighting the need for novel antimicrobial agents. In this study, we aimed to nanoencapsulate mānuka oil and its purified β-triketones in chitosan and evaluate the antimicrobial potential of these formulations for oral applications. METHODS: Chitosan nanoparticles were produced containing mānuka oil and its purified β-triketone components. The ratios of chitosan to sodium tripolyphosphate (TPP) of 5:1, 4:1, and 3:1 were investigated at two pH levels for chitosan and TPP. Nanoparticles were investigated for size and uniformity (polydispersity index: PDI). The antimicrobial activity of the produced nanoparticles was evaluated against E. faecalis, S. mutans, P. gingivalis, and S. aureus. The nanoparticles were assessed for yield, encapsulation efficiency (EE), and biocompatibility, and were visualized using light and scanning electron microscopy. RESULTS: The optimal conditions for producing nanoparticles were a chitosan: TPP ratio of 5:1, with chitosan adjusted to pH 5.5 and TPP maintained at its unadjusted pH 9. The particle sizes were 327 nm (PDI: 0.654), 336 nm (PDI: 0.471), and 288 nm (PDI: 0.379) for unloaded chitosan, chitosan encapsulating mānuka oil, and purified β-triketone, respectively. Freeze-dried yield was 266-370 mg/ml with a high EE of 89%. The release profile for mānuka oil showed 91% by day 5, while for β-triketone, 93% was released by day 7. Mesenchymal stem cells showed reduced metabolic activity with >6.25 mg/ml of nanoparticles, regardless of payload. CONCLUSIONS: Mānuka oil and β-triketone nanoparticles were produced with promising attributes as antimicrobials for intraoral application.