Nanoencapsulation of mānuka oil and β-triketones for antimicrobial delivery in oral wounds

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.