Chlorhexidine-miconazole-loaded iron oxide nanoparticles inhibit denture stomatitis biofilms in vitro

This study used chitosan (CS)-coated iron oxide nanoparticles (IONPs) to create a dual-nanocarrier consisting of chlorhexidine (CHX) and miconazole (MCZ) and assessed their impact on a denture stomatitis microcosm biofilm.

CHX and MCZ were immobilized on IONPs functionalized with CS and the nanocarriers were characterized by physicochemical tests. Biofilms originating from the saliva of patients with denture stomatitis were formed on acrylic surfaces and were treated with IONPs-CS carrying different concentrations of CHX-MCZ (7.8, 19.5, 39, or 78 µg/mL). Untreated biofilms served as the negative control (NC), whereas IONPs, CS, and CHX-MCZ served as controls. Biomass, metabolism, lactic acid generation, number of cultivable cells, cell viability, and biofilm thickness were assessed. Analysis of Variance (ANOVA) or Kruskal-Wallis tests were used to examine all results, and then the Student-Newman-Keuls post hoc test was applied (α=0.05).

The nanocarriers were spherical with a diameter of 6.6 nm. The nanocarrier concentration of 78 µg/mL increased the biomass compared with NC. This nanocarrier compound also reduced metabolism and lactic acid generation, surpassing the effects of CHX-MCZ. For the total microorganism and Streptococcus mutans loads, IONPs-CS-CHX-MCZ behaved similarly to CHX-MCZ, and both led to significant reductions relative to NC. The nanocarrier reduced cell viability and increased biofilm thickness compared with the NC.

The dual nanocarriers showed an antibiofilm effect equal to or greater than that of CHX-MCZ, depending on the variable analyzed. Nanotherapy has potential for use in mouthwashes, denture cleaning solutions, or anti-biofilm mucoadhesive coatings.