Virginia Serra Souza

Nitro-functionalized imidazolium salts were applied as acidic catalysts for the degradation of cellulose into 5-hydroxymethylfurfural (HMF). The catalytic systems based on [NO₂HMIm][X] (X = TsO, Cl, NTf₂, CF₃CO₂), dissolved in [BMIm][Cl], were capable of producing HMF, glucose, fructose, formic acid, and levulinic acid as products of cellulose degradation at 130 ^oC. In particular, HMF was obtained in up to 17% yield using 10.8 mol% of [NO₂HMIm][TsO], representing one of the most active protic imidazolium salts reported in the literature for the transformation of cellulose under relatively mild conditions. Indeed, this work presents cost-effective and easily synthesized nitro-functionalized imidazolium salts as efficient catalysts for biomass conversion, offering a sustainable alternative to conventional SO₃H-based imidazolium ILs. Therefore, the strategy of modifying the acidity of a protic IL by incorporating a nitro group in the imidazolium ring was successfully achieved, as observed in the degradation of cellulose, and can be extended to other acid-catalyzed reactions of biomass-derived compounds.

1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI.NTf₂) is a hydrophobic ionic liquid with potential antibacterial properties for dental materials. This study aimed to (1) incorporate different mass fractions of BMI.NTf₂ into a dental adhesive and (2) assess its impact on physical and chemical properties. Adhesive resins were prepared with 1 (G_1%), 2.5 (G_2.5%), and 5 wt.% (G_5%) BMI.NTf₂, with a control group (G_CTRL) lacking the ionic liquid. Evaluations included polymerization kinetics, degree of conversion (DC), softening in solvent (ΔKHN%), and ultimate tensile strength (UTS). Groups with BMI.NTf₂ showed accelerated polymerization kinetics, with G_5% achieving a higher DC and ΔKHN% compared to G_CTRL (p < 0.05). Lower concentrations (1% and 2.5%) did not affect ΔKHN%, and no significant differences were found in UTS across groups (p > 0.05). Notably, 2.5 wt.% of BMI.NTf₂ increased the DC without affecting other properties, indicating optimal polymerization rates and handling characteristics. These results support the development of BMI.NTf₂-based antibacterial adhesives that may assist in preventing secondary caries in restorative dentistry.

The decrease in the effectiveness of current treatments for hair dermatosis caused by the resistance to antifungals affects patients, causing many cases of recurrence. Thus, the search for low-cost materials with potential antifungal and antibiofilm effects that are easy to prepare, water-soluble, polydisperse and chemically green is significant. Thus, the purpose of this research is to develop mini-emulsions based on protic ionic liquids and oleic acid that present antibiofilm activity against strains related to animal hair dermatophytosis. The effects of three different protic ionic liquids (PILs), 2-hydroxy diethylammonium lactate (2-HDEALa), 2-hydroxy diethylammonium salicylate (2-HDEASa) and 2-hydroxy diethylammonium maleate (2-HDEAMa), on the size, stability and antibiofilm activity of the mini-emulsions were investigated. The effects of PILs and oleic acid concentrations on the size, polydispersity and electrostatic stability of mini-emulsions were evaluated using dynamic light scattering and electrophoretic light scattering. The raw materials and mini-emulsions were also characterized using nuclear magnetic resonance (NMR) spectroscopy and fluorescence experiments including confocal microscopy. In addition, the potential of the synthesized nanomaterials to eradicate Microsporum canis biofilms on animal hair was evaluated. As a result, it was observed that mini-emulsions with smaller sizes, a lower polydispersity index and high electrostatic stability were produced with 10 mM oleic acid and 20 mM 2-HDEALa, 50 mM 2-HDEAMa and 50 mM 2-HDEAMa using a simple and low-cost synthetic method. Furthermore, the confocal microphotographs demonstrated that the mini-emulsions had a spherical shape and the fluorescence and NMR analyses showed that the PILs 2-HDEALa and 2-HDEAMa efficiently covered the oleic acid in the mini-emulsions. Regarding the treatment of dermatophytosis in animal hair using mini-emulsions, it was found that these nanomaterials eliminated 100% of the M. canis biofilm. In conclusion, chemically green molecules such as the PILs 2-HDEALa, 2-HDEAMa and 2-HDEASa were able to form mini-emulsions easily and inexpensively with oleic acid. The PILs presented a synergetic effect with oleic acid, providing the complete eradication of the M. canis biofilm. Therefore, the results of this study suggest that these nanomaterials could be a potential water-soluble formulation to be used as a lotion in the treatment of animal hair dermatoses.

Resin infiltrants have been effectively applied in dentistry to manage non-cavitated carious lesions in proximal dental surfaces. However, the common formulations are composed of inert methacrylate monomers. In this study, we developed a novel resin infiltrant with microcapsules loaded with an ionic liquid (MC-IL), and analyzed the physical properties and cytotoxicity of the dental resin. First, the ionic liquid 1-n-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMI.NTf₂) was synthesized. BMI.NTf₂ has previously shown antibacterial activity in a dental resin. Then, MC-IL were synthesized by the deposition of a preformed polymer. The MC-IL were analyzed for particle size and de-agglomeration effect via laser diffraction analysis and shape via scanning electron microscopy (SEM). The infiltrants were formulated, and the MC-IL were incorporated at 2.5%, 5%, and 10 wt%. A group without MC-IL was used as a control. The infiltrants were evaluated for ultimate tensile strength (UTS), contact angle, surface free energy (SFE), and cytotoxicity. The MC-IL showed a mean particle size of 1.64 (±0.08) μm, shriveled aspect, and a de-agglomeration profile suggestive of nanoparticles' presence in the synthesized powder. There were no differences in UTS among groups (p > 0.05). The incorporation of 10 wt% of MC-IL increased the contact angle (p < 0.05), while the addition from 5 wt% reduced the SFE in comparison to the control group (p < 0.05). The human cell viability was above 90% for all groups (p > 0.05). The incorporation of microcapsules as a drug-delivery system for ionic liquids may be a promising strategy to improve dental restorative materials.

Purpose: To synthesize tantalum oxide quantum dots (Ta(2)O(5)QDs) using an imidazolium ionic liquid as a precursor and evaluate the effect of its addition to an experimental adhesive resin on the degree of conversion (DC) and antibacterial activity. Materials and Methods: Ta(2)O(5)QDs was synthesized from the hydrolysis of an imidazolium ionic liquid (1-n-decyl-3-methylimidazolium hexachlorotantalate [DMI center dot TaCl6]) and evaluated by transmission electron microscopy (TEM). The adhesive was formulated with 66.7 wt% bisphenol A-glycidyl methacrylate (bis-GMA), 33.3 wt% 2-hydroxyethyl methacrylate (HEMA) with a photoinitiator/co-initiator system. In one group, Ta(2)O(5)QDS was added to the adhesive at 1 wt% Ta(2)O(5)QDs) and one group remained without Ta(2)O(5)QDS as control (CTRL). The adhesives were evaluated for DC by Fourier Transform Infrared spectroscopy. Direct contact inhibition assay was used to evaluate the antibacterial activity of the experimental adhesive resins against biofilm formation and planktonic bacteria. Results: Ta(2)O(5)QDs had a particle size distribution of 1.52 +/- 0.73 nm. DC was 50.91 +/- 4.94% for CTRL and 55.4 +/- 4.58% for Ta(2)O(5)QDs (p = 0.310). Ta(2)O(5)QDs showed less Streptococcus mutans biofilm formation on adhesive surfaces (p = 0.013). There was no statistically significant difference in terms of antibacterial activity against planktonic bacteria (p = 0.079). Conclusion: Non-agglomerated Ta(2)O(5)QDs synthesized from an imidazolium ionic liquid provided antibacterial activity to the experimental adhesive resin against biofilm formation of Streptococcus mutans.