Effects of Antifungal Carriers Based on Chitosan-Coated Iron Oxide Nanoparticles on Microcosm Biofilms

Abstract

Resistance of Candida species to conventional therapies has motivated the development of antifungal nanocarriers based on iron oxide nanoparticles (IONPs) coated with chitosan (CS). This study evaluates the effects of IONPs-CS as carriers of miconazole (MCZ) or fluconazole (FLZ) on microcosm biofilms. Pooled saliva from two healthy volunteers supplemented with C. albicans and C. glabrata was the inoculum for biofilm formation. Biofilms were formed for 96 h on coverslips using the Amsterdam Active Attachment model, followed by 24 h treatment with nanocarriers containing different concentrations of each antifungal (78 and 156 µg/mL). MCZ or FLZ (156 µg/mL), and untreated biofilms were considered as controls. Anti-biofilm effects were evaluated by enumeration of colony-forming units (CFUs), composition of the extracellular matrix, lactic acid production, and structure and live/dead biofilm cells (confocal laser scanning microscopy-CLSM). Data were analyzed by one-way ANOVA and Fisher LSD’s test (α = 0.05). IONPs-CS carrying MCZ or FLZ were the most effective treatments in reducing CFUs compared to either an antifungal agent alone for C. albicans and MCZ for C. glabrata. Significant reductions in mutans streptococci and Lactobacillus spp. were shown, though mainly for the MCZ nanocarrier. Antifungals and their nanocarriers also showed significantly higher proportions of dead cells compared to untreated biofilm by CLSM (p < 0.001), and promoted significant reductions in lactic acid, while simultaneously showing increases in some components of the extracellular matrix. These findings reinforce the use of nanocarriers as effective alternatives to fight oral fungal infections.

Sustainable synthesis of microwave-assisted IONPs using Spinacia oleracea L. for control of fungal wilt by modulating the defense system in tomato plants

“…Cell genotoxicity and cytotoxicity are affected by the surface charge of IONPs, and NPs with positive charges tend to be more lethal, endure adsorptive endocytosis, and display non-specific interactions with the negatively charged cell membrane, hence distressing the membrane permeability by enhancing intracellular accumulation [ 63 ]. Thus far, it has been documented that IONPs exert anti-microbial effects by inducing the production of ROS, following disruption of electron transport by microbes, NADH oxidation, and cellular homeostasis, thus contributing to anti-fungal effects [ 64 ]. No doubt, magnetic oxide NPs retain the ability to aggravate oxidative stress by disturbing the redox potential of cells and augmenting the host anti-microbial resistance, by targeting the infection sites with a direct approach, to eradicate microbial pathogens [ 61 – 65 ].…”

Smart dental materials for antimicrobial applications

“…Tokajuk et al (2017) developed a nanosystem with magnetic NPs coated with aminosilane and CHX for antifungal effects against Candida biofilms [ 296 ]. Chitosan-coated Fe 3 O 4 NPs have also been used as CHX carriers to remove S. mutans , C. albicans biofilms, and others [ 252 , [297] , [298] , [299] ].…”

Application of Iron Nanoparticle-Based Materials in the Food Industry

“…This mechanism effectively weakens the microorganisms and reduces the supply of oxygen for respiration [ 146 ]. In addition, the same effects as in bacterial cells are displayed; i.e., IONPs are able to depolarize the cell membrane to induce the production of ROS and generate oxidative stress that disrupts cellular homeostasis [ 152 ].…”