Antifungal activity of dental resins containing amphotericin B-conjugated nanoparticles

To evaluate the antifungal activity, biocompatibility and mechanical properties of dental resins containing silica nanoparticles functionalized with amphotericin B (SNP-DexOxAmB) against five species of Candida.

Dental resin composites (Spectrum, Dentsply DeTrey, GmbH, Germany) having 2% (w/w) of SNP-DexOxAmB (SNPs of 5 and 80nm, denoted as SNP5 and SNP80) were aged for 10, 20 and 30 days at 37°C, in phosphate buffer saline buffer pH 7.4 (PBS). At different time, the antifungal activity was evaluated by a direct contact assay against 1×10(4)cells of Candida. The biocompatibility of the resins was tested against human fibroblasts, endothelial cells and red blood cells.

Dental resins containing SNP5-DexOxAmB have high (1×10(4)cells killed in 5h by ∼70mg of dental resin composite containing 2% (w/w) of SNP-DexOxAmB) and durable (for at least 1 month) antifungal activity against five strains of Candida. The incorporation of the nanoparticles (NPs) had no significant change in the mechanical properties of the resin, specifically the flexural strength and modulus. Our results further show that the antifungal activity is mainly mediated by direct contact and not by leaching of NPs from the resin. Resins incorporating SNP5-DexOxAmB have longer-term antifungal activity than SNP80-DexOxAmB. The antimicrobial activity of resins with SNP5-DexOxAmB persists after 4 cycles of re-use and it is superior to the activity obtained for dental resins containing silver NPs. In addition, dental resins incorporating SNP5-DexOxAmB are non-cytotoxic against human skin fibroblasts and human umbilical vein endothelial cells, and non-hemolytic against human red blood cells.

The incorporation of SNP5-DexOxAmB in dental resins resulted in a non-cytotoxic composite with high and durable antifungal activity.