Ethosomal nanocarrier encapsulating curcumin for antimicrobial photodynamic therapy: efficacy analysis against mature Streptococcus mutans biofilm

BACKGROUND: Biofilms contribute to the dental calculus formation, which in turn deteriorates oral and systemic health. The use of antimicrobial photodynamic therapy (PDT) may be limited by problems with photosensitizer penetration. In addition, toxicity issues severely limit the potential of PDT. In this study, the selected photosensitizer, curcumin (Cur), was loaded into ethosome (Eth) nanocarriers to enhance the effect of Cur for potential PDT against the mature Streptococcus mutans biofilm. METHODS: The Cur-Eth formulation was characterized and evaluated for its PDT efficacy in destroying the mature S. mutans biofilm. Colorimetric and confocal microscopy assay were used for this purpose. Cur in free and ethosomal form was also evaluated for in vitro cytotoxicity study on human gingival fibroblasts (HGFs) by MTT assay. RESULTS: The formulation has spherical structures with a mean vesicle size of 191.3 ± 6.5 nm and an EE of 87.32 ± 1.43%. Cur-Eth showed good biocompatibility, which was confirmed by the cellular viability of HGFs. Photoactivated Cur-Eth showed 39.62 ± 8.50% reduction in mature S. mutans biofilm (P < 0.001), which was not a significant difference compared to 5% sodium hypochlorite (NaOCl) with 49.52 ± 0.23% reduction (P = 0.608). In addition, confocal microscopy showed cell disintegration of Cur-Eth after LED irradiation. CONCLUSION: The present study provides a strong rationale and motivation for further investigation of Eth as a potential therapeutic strategy, especially in the case of older biofilms.