Biofilm-associated genes as potential molecular targets of nano-FeO in Candida albicans.

Background: There are few effective treatments for Candida biofilm-associated infections. The present study demonstrated changes in the expression of biofilm-associated genes in Candida albicans treated with magnetic iron oxide nanoparticles (denoted as nano-FeO).

Methods: Nano-FeO was biologically synthesized using Bacillus licheniformis, Bacillus cereus, and Fusarium oxysporum. Additionally, the biologically synthesized nano-FeO was characterized by visual observation; ultraviolet-visible spectroscopy, scanning electron microscopy, X-ray diffraction spectroscopy, and Fourier transform infrared spectroscopy. The biologically synthesized nano-FeO was tested for growth and biofilm formation in C. albicans. Furthermore, quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used to study the inhibition of biofilm-associated genes in C. albicans treated with nano-FeO.

Results: The production of biologically synthesized nano-FeO was confirmed using extensive characterization methods. The nano-FeO inhibited growth and biofilm formation. Nano-FeO exhibited growth inhibition with minimum inhibition concentrations (MICs) of 50 to 200 μg mL. The anti-biofilm effects of nano-FeO were shown by 2,3-bis (2-methoxy-4-nitro-5 sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay, crystal violet staining, and light field microscopy. The gene expression results showed that the downregulation of BCR1, ALS1, ALS3, HWP1, and ECE1 genes inhibited the biofilm formation in C. albicans. ALS1 reduction was greater than others, with downregulation of 1375.83-, 1178.71-, and 768.47-fold at 2 × MIC, 1 × MIC, and ½ × MIC of nano-FeO, respectively.

Conclusion: Biofilm-associated genes as potential molecular targets of nano-FeO in C. albicans may be an effective novel treatment strategy for biofilm-associated infections.