Medical applications and biotechnological advances, including magnetic resonance imaging, cell separation and detection, tissue repair, magnetic hyperthermia and drug delivery, have strongly benefited from employing iron oxide nanoparticles (IONPs) due to their remarkable properties, such as superparamagnetism, size and possibility of receiving a biocompatible coating. Ongoing research efforts focus on reducing drug concentration, toxicity, and other side effects, while increasing efficacy of IONPs-based treatments. This review highlights the methods of synthesis and presents the most recent reports in the literature regarding advances in drug delivery using IONPs-based systems, as well as their antimicrobial activity against different microorganisms. Furthermore, the toxicity of IONPs alone and constituting nanosystems is also addressed.

The prevention of adhesion of Candida cells to acrylic surfaces can be regarded as an alternative to prevent denture stomatitis. The use of quorum sensing molecules, such as tyrosol, could potentially interfere with the adhesion process. Therefore, the aim of this study was to assess the effect of tyrosol on adhesion of single and mixed cultures of Candida albicans and Candida glabrata to acrylic resin surfaces. Tyrosol was diluted in each yeast inoculum (10(7) cells/ml in artificial saliva) at 25, 50, 100, and 200 mM. Then, each dilution was added to wells of 24-well plates containing the acrylic specimens, and the plates were incubated at 37°C for 2 h. After, the effect of tyrosol was determined by total biomass quantification, metabolic activity of the cells and colony-forming unit counting. Chlorhexidine gluconate (CHG) was used as a positive control. Data were analyzed using analysis of variance (ANOVA) and the Holm-Sidak post hoc test (α = 0.05). The results of total biomass quantification and metabolic activity revealed that the tyrosol promoted significant reductions (ranging from 22.32 to 86.16%) on single C. albicans and mixed cultures. Moreover, tyrosol at 200 mM and CHG significantly reduced (p < 0.05) the number of adhered cells to the acrylic surface for single and mixed cultures of both species, with reductions ranging from 1.74 to 3.64-log10. In conclusion, tyrosol has an inhibitory effect on Candida adhesion to acrylic resin, and further investigations are warranted to clarify its potential against Candida infections.

This is the first study showing the antibiofilm effect of tyrosol on Candida species and Strep. mutans in single and mixed cultures. These results may be useful in the development of topical therapies focused on preventing biofilm-associated oral diseases, such as denture stomatitis and dental caries.

The aim of this study was to evaluate the effect of the QS molecule farnesol on single and mixed species biofilms formed by Candida albicans and Streptococcus mutans. The anti-biofilm effect of farnesol was assessed through total biomass quantification, counting of colony forming units (CFUs) and evaluation of metabolic activity. Biofilms were also analyzed by scanning electron microscopy (SEM). It was observed that farnesol reduced the formation of single and mixed biofilms, with significant reductions of 37% to 90% and 64% to 96%, respectively, for total biomass and metabolic activity. Regarding cell viability, farnesol treatment promoted significant log reductions in the number of CFUs, ie 1.3-4.2 log10 and 0.67-5.32 log10, respectively, for single and mixed species biofilms. SEM images confirmed these results, showing decreases in the number of cells in all biofilms. In conclusion, these findings highlight the role of farnesol as an alternative agent with the potential to reduce the formation of pathogenic biofilms.

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