Superparamagnetic Iron Oxide Nanoparticles and Essential Oils: A New Tool for Biological Applications

Effect of Highly Hydrophilic Superparamagnetic Iron Oxide Nanoparticles on Macrophage Function and Survival

Superparamagnetic iron oxide nanoparticles (SPIONs) have garnered significant attention in the medical sector due to their exceptional superparamagnetic properties and reliable tracking capabilities. In this study, we investigated the immunotoxicity of SPIONs with a modified surface to enhance hydrophilicity and prevent aggregate formation. The synthesized SPIONs exhibited a remarkably small size (~4 nm) and underwent surface modification using a novel "haircut" reaction strategy. Experiments were conducted in vitro using a human monocytic cell line (THP-1). SPIONs induced dose-dependent toxicity to THP-1 cells, potentially by generating ROS and initiating the apoptotic pathway in the cells. Concentrations up to 10 μg/mL did not affect the expression of Nrf2, HO-1, NF-κB, or TLR-4 proteins. The results of the present study demonstrated that highly hydrophilic SPIONs were highly toxic to immune cells; however, they did not activate pathways of inflammation and immune response. Further investigation into the mechanisms of cytotoxicity is warranted to develop a synthetic approach for producing effective, highly hydrophilic SPIONs with little to no side effects.

Evaluation of the Antibacterial Properties of Iron Oxide, Polyethylene Glycol, and Gentamicin Conjugated Nanoparticles against Some Multidrug-Resistant Bacteria

Antibacterial resistance is observed as a public health issue around the world. Every day, new resistance mechanisms appear and spread over the world. For that reason, it is imperative to improve the treatment schemes that have been developed to treat infections caused by wound infections, for instance, Staphylococcus epidermidis (S. epidermidis), Proteus mirabilis (P. mirabilis), and Acinetobacter baumannii (A. baumannii). In this case, we proposed a method that involves mixing the Gentamicin (Gen) with iron oxide nanoparticles (Fe3O4 NPs) and a polymer (polyethylene glycol (PEG)) with Fe3O4 NPs. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize Fe3O4 NPs. Zeta potential and dynamic light scattering (DLS) were also assessed. The antibacterial activity of Fe3O4 NPs, Fe3O4 NPs+PEG, Fe3O4 NPs+Gen, and Fe3O4 NPs+PEG+Gen composites was investigated. The results showed a significant improvement in the antibacterial activity of nanoparticles against bacterial isolates, especially for the Fe3O4 NPs+PEG+Gen as the diameter of the inhibition zone reached 26.33 ± 0.57 mm for A. baumannii, 25.66 ± 0.57 mm for P. mirabilis, and 23.66 ± 0.57 mm for S. epidermidis. The Fe3O4 NPs, Fe3O4 NPs+PEG, Fe3O4+Gen, and Fe3O4+PEG+Gen also showed effectiveness against the biofilm produced by these isolated bacteria. The minimum inhibitory concentration (MIC) of Fe3O4 NPs for S. epidermidis was 25 µg mL−1 and for P. mirabilis and A. baumannii was 50 µg mL−1. The findings suggest that the prepared nanoparticles could be potential therapeutic options for treating wound infections caused by S. epidermidis, P. mirabilis, and A. baumannii.

Green Synthesis and Characterization of Iron Nanoparticles Synthesized from Aqueous Leaf Extract of Vitex leucoxylon and Its Biomedical Applications

The cold extraction method was used to obtain the aqueous extract of Vitex leucoxylon leaves in a ratio of 1:10. Iron nanoparticles (FeNPs) were synthesized using aqueous leaf extract of V. leucoxylon as a reducing agent. The phytoreducing approach was used to make FeNPs by mixing 1 mL of plant extract with 1 mM of ferric sulfate. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Ultraviolet–visible spectroscopy (UV-Vis), and energy-dispersive X-ray spectroscopy were used to examine the synthesized FeNPs. The reducing reaction was shown by a change in the color of the solution, and the formation of black color confirms that FeNPs have been formed. The greatest absorption peak (max) was found at 395 nm in UV-Vis spectral analysis. The FTIR spectra of V. leucoxylon aqueous leaf extract showed shifts in some peaks, namely 923.96 cm⁻¹ and 1709.89 cm⁻¹, with functional groups carboxylic acids, unsaturated aldehydes, and ketones, which were lacking in the FTIR spectra of FeNPs and are responsible for FeNPs formation. FeNPs with diameters between 45 and 100 nm were observed in SEM images. The creation of FeNPs was confirmed by EDX, which shows a strong signal in the metallic iron region at 6–8 Kev. XRD revealed a crystalline nature and an average diameter of 136.43 nm. Antioxidant, anti-inflammatory, cytotoxic, and wound healing in vitro tests reported significant activity of the FeNPs. The cumulative findings of the present study indicate that the green synthesis of FeNPs boosts its biological activity and may serve as a possible dermal wound-healing agent and cytotoxic agent against cancer. Future study is needed on the identification of mechanisms involved in the synthesis of FeNPs by V. leucoxylon and its biomedical applications.

Overcoming Multidrug Resistance in Salmonella spp. Isolates Obtained From the Swine Food Chain by Using Essential Oils: An in vitro Study

Antimicrobial resistance (AMR) is a global concern, and new approaches are needed to circumvent animal and food-borne resistant pathogens. Among the new strategies, the combination of antibiotics with natural compounds such as essential oils (EOs) could be an alternative to challenge bacterial resistance. The present study evaluates the phenotypic and genotypic antibiotic resistance of 36 Salmonella enterica (16 S. Typhimurium, 3 monophasic variant S. Typhimurium, 8 S. Enteritidis, 6 S. Rissen, 1 S. Typhi, and 2 S. Derby) strains, isolated from the swine production chain. The isolates displayed phenotypic resistance to gentamicin, amikacin, tobramycin, and tetracycline, while the resistance genes most commonly detected were parC, catA, nfsB, nfsA, blaTEM, tetA, and tetB. Then 31/36 Salmonella isolates were chosen to evaluate resistance to tetracycline and Thymus vulgaris, Eugenia caryophyllata, and Corydothymus capitatus EOs by determining minimum inhibitory concentrations (MICs). Finally, the synergistic effect between tetracycline and each EOs was evaluated by the checkerboard method, calculating the fractional inhibitory concentration (FIC) index. Among the EOs, C. capitatus displayed the best bioactivity in terms of MICs, with the lowest values (0.31 and 0.625 μl/ml). On the contrary, the strains showed the ability to grow in the presence of the maximum concentration of tetracycline employed (256 μg/ml). While not displaying a real synergism according to the FIC index, the combination of tetracycline compounds and the three EOs resulted in a significant reduction in the MIC values to tetracycline (4 μg/ml), suggesting a restoration of the susceptibility to the antibiotic in Salmonella spp.

Nanoparticles—Attractive Carriers of Antimicrobial Essential Oils

Microbial pathogens are the most prevalent cause of chronic infections and fatalities around the world. Antimicrobial agents including antibiotics have been frequently utilized in the treatment of infections due to their exceptional outcomes. However, their widespread use has resulted in the emergence of multidrug-resistant strains of bacteria, fungi, viruses, and parasites. Furthermore, due to inherent resistance to antimicrobial drugs and the host defence system, the advent of new infectious diseases, chronic infections, and the occurrence of biofilms pose a tougher challenge to the current treatment line. Essential oils (EOs) and their biologically and structurally diverse constituents provide a distinctive, inexhaustible, and novel source of antibacterial, antiviral, antifungal, and antiparasitic agents. However, due to their volatile nature, chemical susceptibility, and poor solubility, their development as antimicrobials is limited. Nanoparticles composed of biodegradable polymeric and inorganic materials have been studied extensively to overcome these limitations. Nanoparticles are being investigated as nanocarriers for antimicrobial delivery, antimicrobial coatings for food products, implantable devices, and medicinal materials in dressings and packaging materials due to their intrinsic capacity to overcome microbial resistance. Essential oil-loaded nanoparticles may offer the potential benefits of synergism in antimicrobial activity, high loading capacity, increased solubility, decreased volatility, chemical stability, and enhancement of the bioavailability and shelf life of EOs and their constituents. This review focuses on the potentiation of the antimicrobial activity of essential oils and their constituents in nanoparticulate delivery systems for a wide range of applications, such as food preservation, packaging, and alternative treatments for infectious diseases.

Sepsis diagnosis and treatment using nanomaterials

Sepsis is a life-threatening reaction that occurs when the body's severe response to an infection damages the host's own tissues. Sepsis has been globally recognized as a fatal disease. Rapid treatment of sepsis requires prompt identification, administering antibiotics, careful hemodynamic support, and treating the cause of the infection. Clinical outcomes of sepsis depend on early diagnosis and appropriate treatment. Unfortunately, current sepsis diagnosis and treatment, such as polymerase chain reaction-based assay, blood culture assay, and antibiotic therapy, are ineffective; consequently, sepsis-related mortality remains high and increases antimicrobial resistance. To overcome this challenge, nanotechnology, which involves engineering at a nanoscale, is used for diagnosing and treating sepsis. Preclinical models have shown protective effects and potential utility in managing septic shock. Furthermore, nanotechnology treatments based on diverse materials result in the effective treatment of sepsis, improving the survival rate. In this review, we present an overview of the recent research advancements in nanotechnology to diagnose and treat sepsis with a brief introduction to sepsis.

Multifunctional liquid marbles to stabilize and transport reactive fluids

The self-organized transport and delivery of reactive liquids without spillage or loss of activity have been among the most daunting challenges for a long time. In this direction, we employ the concept of forming "liquid marbles" (LMs) to encapsulate and transport reactive hydrogen peroxide (H2O2) coated with functional microparticles. For example, peroxide marbles coated with a toner ink display remote-controlled magnetotactic movement inside a fluidic medium, thus overcoming the weaknesses associated with use of the bare droplets. Interestingly, in such a scenario, the coating of the marbles could also be removed or reformed by bringing the magnet towards or away from the marble. In this way, this process could ensure an on-demand remotely guided coating on the peroxide droplet or its removal. The liquid marbles carrying peroxide solutions are found to preserve the activity of the peroxide and exhibit a low evaporation rate compared with the uncoated peroxide fuel. Interestingly, oil droplets floating on the water could be recovered by introducing the armoured LMs into water under magnetic guidance. Further, the functionalized marbles could be employed as suicide bags for the on-demand delivery of reactive materials in targeted locations. Preliminary research on the antibacterial activity of such liquid marbles has proven to be effective in bacterial killing, which may create new avenues for emerging antibacterial and antibiofilm applications. Finally, such functionalized LMs have been employed to investigate the effects of surface charge on attachment of recombinant Escherichia coli bacteria expressing green fluorescent protein and monitoring the real-time imaging of bacterial death attached to the marble surface.

Metal Nano/Microparticles for Bioapplications

Nano/micro particles are considered to be the most valuable and important functional materials in the field of materials science and engineering [...].

MAPLE Coatings Embedded with Essential Oil-Conjugated Magnetite for Anti-Biofilm Applications

The present study reports on the development and evaluation of nanostructured composite coatings of polylactic acid (PLA) embedded with iron oxide nanoparticles (Fe₃O₄) modified with Eucalyptus (Eucalyptus globulus) essential oil. The co-precipitation method was employed to synthesize the magnetite particles conjugated with Eucalyptus natural antibiotic (Fe₃O₄@EG), while their composition and microstructure were investigated using grazing incidence X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The matrix-assisted pulsed laser evaporation (MAPLE) technique was further employed to obtain PLA/Fe₃O₄@EG thin films. Optimal experimental conditions for laser processing were established by complementary infrared microscopy (IRM) and scanning electron microscopy (SEM) investigations. The in vitro biocompatibility with eukaryote cells was proven using mesenchymal stem cells, while the anti-biofilm efficiency of composite PLA/Fe₃O₄@EG coatings was assessed against Gram-negative and Gram-positive pathogens.