Iron Oxide-Silica Core-Shell Nanoparticles Functionalized with Essential Oils for Antimicrobial Therapies

Aminoacid functionalised magnetite nanoparticles Fe3O4@AA (AA = Ser, Cys, Pro, Trp) as biocompatible magnetite nanoparticles with potential therapeutic applications

Magnetic nanoparticles (MNPs) are of great interest for their wide applications in biomedical applications, such as bioimaging, antitumoral therapies, regenerative medicine, and drug delivery. The work aimed to obtain biocompatible magnetite nanoparticles coated with amino acids of the general formula Fe3O4@AA (AA = L-tryptophan, L-serine, L-proline and L-cysteine) for potential therapeutic application in anticancer drug delivery. The obtained materials were characterised using XRD, FTIR, DLS analysis, SEM, thermogravimetry (TG), differential scanning calorimetry (DSC), and UV-vis spectroscopy. The photocatalytic, cytotoxic and antimicrobial activity tests of the obtained materials were carried out. The choice of amino acid determines the properties of the material and its future use, for example, Fe3O4@Cys supports radical production, which may increase the efficiency of catalytic degradation, while tryptophan captures radicals, which may be an advantage in several biomedical applications. Fe3O4@Trp exhibited good antimicrobial activity (MBEC and MIC) against E. coli ATCC 25922, P. aeruginosa ATCC 27853 and C. albicans ATCC 10231 while Fe3O4@Pro exhibited the best results against S. aureus ATCC 25923.

Irinotecan-loaded magnetite-silica core-shell systems for colorectal cancer treatment

Colorectal cancer represents a worldwide spread type of cancer and it is regarded as one of the leading death causes, along with lung, breast, and prostate cancers. Since conventional surgical resection and chemotherapy proved limited efficiency, the use of alternative drug delivery systems that ensure the controlled release of cytostatic agents possess immense potential for treatment. In this regard, the present study aimed to develop and evaluate the efficiency of a series of irinotecan-loaded magnetite-silica core-shell systems. The magnetite particles were obtained through a solvothermal treatment, while the silica shell was obtained through the Stöber method directly onto the surface of magnetite particles. Subsequently, the core-shell systems were physico-chemically and morpho-structurally evaluated trough X-ray diffraction (XRD) and (high-resolution) transmission electron microscopy ((HR-)TEM) equipped with a High Annular Angular Dark Field Detector (HAADF) for elemental mapping. After the irinotecan loading, the drug delivery systems were evaluated through Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry and differential scanning calorimetry (TG-DSC), and UV-Vis spectrophotometry. Additionally, the Brunauer-Emmett-Teller (BET) method was employed for determining the surface area and pore volume of the systems. The biological functionality of the core-shells was investigated through the MTT assay performed on both normal and cancer cells. The results of the study confirmed the formation of highly crystalline magnetite particles comprising the core and mesoporous silica layers of sizes varying between 2 and 7 nm as the shell. Additionally, the drug loading and release was dependent on the type of the silica synthesis procedure, since the lack of hexadecyltrimethylammonium bromide (CTAB) resulted in higher drug loading but lower cumulative release. Moreover, the nanostructured systems demonstrated a targeted efficiency towards HT-29 colorectal adenocarcinoma cells, as in the case of normal L929 fibroblast cells, the cell viability was higher than for the pristine drug. In this manner, this study provides the means and procedures for developing drug delivery systems with applicability in the treatment of cancer.

Microwave-Assisted Silanization of Magnetite Nanoparticles Pre-Synthesized by a 3D Microfluidic Platform

Magnetite nanoparticles (Fe3O4 NPs) are among the most investigated nanomaterials, being recognized for their biocompatibility, versatility, and strong magnetic properties. Given that their applicability depends on their dimensions, crystal morphology, and surface chemistry, Fe3O4 NPs must be synthesized in a controlled, simple, and reproducible manner. Since conventional methods often lack tight control over reaction parameters and produce materials with unreliable characteristics, increased scientific interest has been directed to microfluidic techniques. In this context, the present paper describes the development of an innovative 3D microfluidic platform suitable for synthesizing uniform Fe3O4 NPs with fine-tuned properties. On-chip co-precipitation was performed, followed by microwave-assisted silanization. The obtained nanoparticles were characterized from the compositional and microstructural perspectives by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, supplementary physicochemical investigations, such as Fourier Transform Infrared Spectroscopy (FT-IR), Kaiser Test, Ultraviolet-Visible (UV-Vis) Spectrophotometry, Dynamic Light Scattering (DLS), and Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) analyses, demonstrated the successful surface modification. Considering the positive results, the presented synthesis and functionalization method represents a fast, reliable, and effective alternative for producing tailored magnetic nanoparticles.

Iron Nanoparticles Open Up New Directions for Promoting Healing in Chronic Wounds in the Context of Bacterial Infection

Metal nanoparticles play an outstanding role in the field of wound healing due to their excellent properties, and the significance of iron, one of the most widely used metals globally, cannot be overlooked. The purpose of this review is to determine the importance of iron nanoparticles in wound-healing dressings. Prolonged, poorly healing wounds may induce infections; wound infections are a major cause of chronic wound formation. The primary components of iron nanoparticles are iron oxide nanoparticles, which promote wound healing by being antibacterial, releasing metal ions, and overcoming bacterial resistance. The diameter of iron oxide nanoparticles typically ranges between 1 and 100 nm. Magnetic nanoparticles with a diameter of less than 30 nm are superparamagnetic and are referred to as superparamagnetic iron oxide nanoparticles. This subset of iron oxide nanoparticles can use an external magnetic field for novel functions such as magnetization and functionalization. Iron nanoparticles can serve clinical purposes not only to enhance wound healing through the aforementioned means but also to ameliorate anemia and glucose irregularities, capitalizing on iron's properties. Iron nanoparticles positively impact the healing process of chronic wounds, potentially extending beyond wound management.

Microfluidic Synthesis of Magnetite Nanoparticles for the Controlled Release of Antibiotics

Magnetite nanoparticles (MNPs) have been intensively studied for biomedical applications, especially as drug delivery systems for the treatment of infections. Additionally, they are characterized by intrinsic antimicrobial properties owing to their capacity to disrupt or penetrate the microbial cell wall and induce cell death. However, the current focus has shifted towards increasing the control of the synthesis reaction to ensure more uniform nanoparticle sizes and shapes. In this context, microfluidics has emerged as a potential candidate method for the controlled synthesis of nanoparticles. Thus, the aim of the present study was to obtain a series of antibiotic-loaded MNPs through a microfluidic device. The structural properties of the nanoparticles were investigated through X-ray diffraction (XRD) and, selected area electron diffraction (SAED), the morphology was evaluated through transmission electron microscopy (TEM) and high-resolution TEM (HR-TEM), the antibiotic loading was assessed through Fourier-transform infrared spectroscopy (FT-IR) and, and thermogravimetry and differential scanning calorimetry (TG-DSC) analyses, and. the release profiles of both antibiotics was determined through UV-Vis spectroscopy. The biocompatibility of the nanoparticles was assessed through the MTT assay on a BJ cell line, while the antimicrobial properties were investigated against the S. aureus, P. aeruginosa, and C. albicans strains. Results proved considerable uniformity of the antibiotic-containing nanoparticles, good biocompatibility, and promising antimicrobial activity. Therefore, this study represents a step forward towards the microfluidic development of highly effective nanostructured systems for antimicrobial therapies.

Preparation of Hydrophobic Octadecylphosphonic Acid-Coated Magnetite Nanoparticles for the Demulsification of n-Hexane-in-Water Nanoemulsions

To design more environmentally friendly, economical, and efficient demulsifiers for oily wastewater treatment, hydrophobic octadecylphosphonic acid (ODPA)-modified Fe3O4 nanoparticles (referred to as Fe3O4@ODPA) were prepared by condensation of hydroxyl groups between ODPA and Fe3O4 nanoparticles using the co-precipitation method. The prepared magnetite nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric/differential thermogravimetric (TG/DTG) analysis. The water contact angles (θW) of Fe3O4@ODPA nanoparticles were more than 120°, indicating hydrophobic nature, and the diameter of the obtained spherical-shaped magnetite nanoparticles was 12-15 nm. The ODPA coating amount (AO) (coating weight per gram Fe3O4) and specific surface area (SO) of Fe3O4@ODPA were 0.124-0.144 g·g-1 and 78.65-91.01 m2·g-1, respectively. To evaluate the demulsification ability, stability, and reusability, the magnetite nanoparticles were used to demulsify an n-hexane-in-water nanoemulsion. The effects of the magnetite nanoparticle dosage (CS), pH value of nanoemulsion, and NaCl or CaCl2 electrolytes on the demulsification efficiency (RO) were investigated. The RO of Fe3O4@ODPA samples was found to be higher than that of bare Fe3O4 samples (S0, ST, and SN) under all CS values. With the increase in CS, the RO of Fe3O4@ODPA samples initially increased and then approached equilibrium value at Cs = 80.0 g·L-1. A maximum RO of ~93% was achieved at CS = 100.0 g·L-1 for the Fe3O4@ODPA sample S2. The pH and two electrolytes had a minor effect on RO. The Fe3O4@ODPA nanoparticles maintained high RO even after being reused for demulsification 11 times. This indicates that the hydrophobic Fe3O4@ODPA samples can be used as an effective magnetite demulsifer for oil-in-water nanoemulsions.

Usnic Acid-Loaded Magnetite Nanoparticles-A Comparative Study between Synthesis Methods

Since cancer is a continuously increasing concern for the general population, more efficient treatment alternatives ought to be developed. In this regard, a promising direction is represented by the use of magnetite nanoparticles (MNPs) to act both as a nanocarrier for the targeted release of antitumoral drugs and as hyperthermia agents. Thus, the present study focused on improving the control upon the outcome properties of MNPs by using two synthesis methods, namely the co-precipitation and microwave-assisted hydrothermal method, for the incorporation of usnic acid (UA), a natural lichen-derived metabolite with proven anticancer activity. The obtained UA-loaded MNPs were thoroughly characterized regarding their morpho-structural and physicochemical properties through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS) and zeta potential, scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). Results demonstrated the formation of magnetite as the unique mineralogical phase through both types of synthesis, with increased uniformity regarding the drug loading efficiency, size, stability, and magnetic properties obtained through the microwave-assisted hydrothermal method. Furthermore, the cytotoxicity of the nanostructures against the HEK 293T cell line was investigated through the XTT assay, which further proved their potential for anticancer treatment applications.

Electrospun Fibrous Silica for Bone Tissue Engineering Applications

The production of highly porous and three-dimensional (3D) scaffolds with biomimicking abilities has gained extensive attention in recent years for tissue engineering (TE) applications. Considering the attractive and versatile biomedical functionality of silica (SiO₂) nanomaterials, we propose herein the development and validation of SiO₂-based 3D scaffolds for TE. This is the first report on the development of fibrous silica architectures, using tetraethyl orthosilicate (TEOS) and polyvinyl alcohol (PVA) during the self-assembly electrospinning (ES) processing (a layer of flat fibers must first be created in self-assembly electrospinning before fiber stacks can develop on the fiber mat). The compositional and microstructural characteristics of obtained fibrous materials were evaluated by complementary techniques, in both the pre-ES aging period and post-ES calcination. Then, in vivo evaluation confirmed their possible use as bioactive scaffolds in bone TE.

Viologen-functionalized magnetic material for the removal of Iodine and benzanthracene in an aqueous solution

The development of magnetically active adsorbents for effective iodine removal would be highly desirable to address environmental pollution and remediation. Herein, we demonstrated the synthesis of Vio@SiO₂@Fe₃O₄ as an adsorbent via surface functionalisation of electron-deficient bipyridium (viologen) units on the surface of magnetically active silica-coated magnetite (Fe₃O₄) core. This adsorbent was characterised thoroughly using various analytical techniques, such as field emission scanning electron microscopy (FESEM), thermal gravimetric analysis, Fourier transform infrared spectroscopy (FTIR), field emission transmission electron microscopy (FETEM), Brunauer-Emmett-Teller (BET) analysis and X-ray photon analysis (XPS). The removal of triiodide from the aqueous solution was monitored via the batch method. It revealed that the complete removal was achieved upon stirring for 70 min. The thermally stable and crystalline Vio@SiO₂@Fe₃O₄ displayed efficient removal capacity even in the presence of other competing ions and at different pHs. The adsorption kinetics data were analysed following the pseudo-first-order and pseudo-second-order models. Further, the isotherm experiment showed that the maximum uptake capacity of iodine is 1.38 g/g. It can be regenerated and reused over multiple cycles to capture iodine. Further, Vio@SiO₂@Fe₃O₄ displayed a good removal capacity toward toxic polyaromatic, Benzanthracene (BzA) pollutant with an uptake capacity of 2445 μg/g. This effective removal of toxic pollutants iodine/benzanthracene was attributed to the strong non-covalent electrostatic and π-π interaction with electron-deficient bipyridium units.

Synergistic Antimicrobial Activity of Magnetite and Vancomycin-Loaded Mesoporous Silica Embedded in Alginate Films

The aim of the present study was to obtain a hydrogel-based film as a carrier for the sustained and controlled release of vancomycin, an antibiotic commonly used in various types of infections. Considering the high-water solubility of vancomycin (>50 mg/mL) and the aqueous medium underlying the exudates, a prolonged release of vancomycin from an MCM-41 carrier was sought. The present work focused on the synthesis of malic acid coated magnetite (Fe3O4/malic) by co-precipitation, synthesis of MCM-41 by a sol-gel method and loading of MCM-41 with vancomycin, and their use in alginate films for wound dressing. The nanoparticles obtained were physically mixed and embedded in the alginate gel. Prior to incorporation, the nanoparticles were characterized by XRD, FT-IR and FT-Raman spectroscopy, TGA-DSC and DLS. The films were prepared by a simple casting method and were further cross-linked and examined for possible heterogeneities by means of FT-IR microscopy and SEM. The degree of swelling and the water vapor transmission rate were determined, considering their potential use as wound dressings. The obtained films show morpho-structural homogeneity, sustained release over 48 h and a strong synergistic enhancement of the antimicrobial activity as a consequence of the hybrid nature of these films. The antimicrobial efficacy was tested against S. aureus, two strains of E. faecalis (including vancomycin-resistant Enterococcus, VRE) and C. albicans. The incorporation of magnetite was also considered as an external triggering component in case the films were used as a magneto-responsive smart dressing to stimulate vancomycin diffusion.

Zinc/Cerium-Substituted Magnetite Nanoparticles for Biomedical Applications

Numerous studies have reported the possibility of enhancing the properties of materials by incorporating foreign elements within their crystal lattice. In this context, while magnetite has widely known properties that have been used for various biomedical applications, the introduction of other metals within its structure could prospectively enhance its effectiveness. Specifically, zinc and cerium have demonstrated their biomedical potential through significant antioxidant, anticancer, and antimicrobial features. Therefore, the aim of the present study was to develop a series of zinc and/or cerium-substituted magnetite nanoparticles that could further be used in the medical sector. The nanostructures were synthesized through the co-precipitation method and their morpho-structural characteristics were evaluated through X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) analyses. Furthermore, the nanostructures were subjected to a ROS-Glo H2O2 assay for assessing their antioxidant potential, MTT assay for determining their anticancer effects, and antimicrobial testing against S. aureus, P. aeruginosa, and C. albicans strains. Results have proven promising for future biomedical applications, as the nanostructures inhibit oxidative stress in normal cells, with between two- and three-fold reduction and cell proliferation in tumor cells; a two-fold decrease in cell viability and microbial growth; an inhibition zone diameter of 4–6 mm and minimum inhibitory concentration (MIC) of 1–2 mg/mL.

Smart Magnetic Drug Delivery Systems for the Treatment of Cancer

Cancer remains the most devastating disease, being one of the main factors of death and morbidity worldwide since ancient times. Although early diagnosis and treatment represent the correct approach in the fight against cancer, traditional therapies, such as chemotherapy, radiotherapy, targeted therapy, and immunotherapy, have some limitations (lack of specificity, cytotoxicity, and multidrug resistance). These limitations represent a continuous challenge for determining optimal therapies for the diagnosis and treatment of cancer. Cancer diagnosis and treatment have seen significant achievements with the advent of nanotechnology and a wide range of nanoparticles. Due to their special advantages, such as low toxicity, high stability, good permeability, biocompatibility, improved retention effect, and precise targeting, nanoparticles with sizes ranging from 1 nm to 100 nm have been successfully used in cancer diagnosis and treatment by solving the limitations of conventional cancer treatment, but also overcoming multidrug resistance. Additionally, choosing the best cancer diagnosis, treatment, and management is extremely important. The use of nanotechnology and magnetic nanoparticles (MNPs) represents an effective alternative in the simultaneous diagnosis and treatment of cancer using nano-theranostic particles that facilitate early-stage detection and selective destruction of cancer cells. The specific properties, such as the control of the dimensions and the specific surface through the judicious choice of synthesis methods, and the possibility of targeting the target organ by applying an internal magnetic field, make these nanoparticles effective alternatives for the diagnosis and treatment of cancer. This review discusses the use of MNPs in cancer diagnosis and treatment and provides future perspectives in the field.

Increasing Bioavailability of Trans-Ferulic Acid by Encapsulation in Functionalized Mesoporous Silica

Two types of mesoporous materials, MCM-41 and MCM-48, were functionalized by the soft-template method using (3-aminopropyl)triethoxysilane (APTES) as a modifying agent. The obtained mesoporous silica materials were loaded with trans-ferulic acid (FA). In order to establish the morphology and structure of mesoporous materials, a series of specific techniques were used such as: X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer-Emmet-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric analysis (TGA). We monitored the in vitro release of the loaded FA at two different pH values, by using simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Additionally, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATCC 10231 were used to evaluate the antimicrobial activity of FA loaded mesoporous silica materials. In conclusion such functionalized mesoporous materials can be employed as controlled release systems for polyphenols extracted from natural sources.

Magnetite-Based Nanostructured Coatings Functionalized with Nigella sativa and Dicloxacillin for Improved Wound Dressings

In this study, we report the performance improvement of wound dressings by covering them with magnetite-based nanostructured coatings. The magnetite nanoparticles (Fe₃O₄ NPs) were functionalized with Nigella sativa (N. sativa) powder/essential oil and dicloxacillin and were synthesized as coatings by matrix assisted pulsed laser evaporation (MAPLE). The expected effects of this combination of materials are: (i) to reduce microbial contamination, and (ii) to promote rapid wound healing. The crystalline nature of core/shell Fe₃O₄ NPs and coatings was determined by X-ray diffraction (XRD). Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA) have been coupled to investigate the stability and thermal degradation of core/shell nanoparticle components. The coatings' morphology was examined by scanning electron microscopy (SEM). The distribution of chemical elements and functional groups in the resulting coatings was evidenced by Fourier transform infrared (FTIR) spectrometry. In order to simulate the interaction between wound dressings and epithelial tissues and to evaluate the drug release in time, the samples were immersed in simulated body fluid (SBF) and investigated after different durations of time. The antimicrobial effect was evaluated in planktonic (free-floating) and attached (biofilms) bacteria models. The biocompatibility and regenerative properties of the nanostructured coatings were evaluated in vitro, at cellular, biochemical, and the molecular level. The obtained results show that magnetite-based nanostructured coatings functionalized with N. sativa and dicloxacillin are biocompatible and show an enhanced antimicrobial effect against Gram positive and Gram negative opportunistic bacteria.

MAPLE Processed Nanostructures for Antimicrobial Coatings

Despite their great benefits for debilitated patients, indwelling devices are prone to become easily colonized by resident and opportunistic microorganisms, which have the ability to attach to their surfaces and form highly specialized communities called biofilms. These are extremely resistant to host defense mechanisms and antibiotics, leading to treatment failure and device replacement, but also to life-threatening complications. In this study, we aimed to optimize a silica (SiO₂)-coated magnetite (Fe₃O₄)-based nanosystem containing the natural antimicrobial agent, eugenol (E), suitable for MAPLE (matrix-assisted pulsed laser evaporation) deposition as a bioactive coating for biomedical applications. X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and transmission electron microscopy investigations were employed to characterize the obtained nanosystems. The in vitro tests evidenced the superior biocompatibility of such nanostructured coatings, as revealed by their non-cytotoxic activity and ability to promote cellular proliferation and sustain normal cellular development of dermal fibroblasts. Moreover, the obtained nanocoatings did not induce proinflammatory events in human blood samples. Our studies demonstrated that Fe₃O₄ NPs can improve the antimicrobial activity of E, while the use of a SiO₂ matrix may increase its efficiency over prolonged periods of time. The Fe₃O₄@SiO₂ nanosystems showed excellent biocompatibility, sustaining human dermal fibroblasts' viability, proliferation, and typical architecture. More, the novel coatings lack proinflammatory potential as revealed by the absence of proinflammatory cytokine expression in response to human blood sample interactions.

Chitosan-Dextran-Glycerol Hydrogels Loaded with Iron Oxide Nanoparticles for Wound Dressing Applications

Natural polymers have shown tremendous potential towards the development of hydrogels with tissue regeneration properties. Among them, chitosan and dextran are polysaccharides widely applied in the wound dressing area owing to their mucoadhesiveness, biodegradability, hemostatic potential, and intrinsic antibacterial activity, while glycerol is a well-known biocompatible solvent extensively used in the manufacture of cosmetic, pharmaceutical, medical, and personal care products. In order to enhance the properties of natural polymer-based hydrogels, the focus has currently shifted towards the addition of nanomaterials with antibacterial and regenerative potential, i.e., iron oxide nanoparticles. Thus, the aim of the present study was to develop a series of chitosan-dextran-glycerol hydrogels loaded with iron oxide nanoparticles, either readily added or formed in situ. The physicochemical properties of the so obtained hydrogels demonstrated an improved dispersibility of the in situ formed magnetite nanoparticles, which further decreases the porosity and swelling ratio of the hydrogels but increases the antimicrobial properties. Additionally, the presence of glycerol enhances the cell viability but reduces the antimicrobial potential. In this context, the results proved promising biological and antimicrobial properties, thus confirming their potential as biomaterials for wound healing and regeneration.

Folic acid-decorated PEGylated magnetite nanoparticles as efficient drug carriers to tumor cells overexpressing folic acid receptor

The improved drug delivery systems (DDS) are needed for the targeted delivery of their therapeutic cargo (biologically active protein/peptide molecules, nucleic acids, vaccines, etc.) to diseased cells. Thus, we aimed to develop magnetite nanoparticles (Fe₃O₄), stabilized with polyethylene glycol (PEG) and decorated (surface-functionalized) with folic acid (FA) (Fe₃O₄@PEG@FA) to ensure targeted internalization in cells expressing the folic acid receptors (FR). The Fe₃O₄@PEG@FA nanoparticles were synthesized by co-precipitation in a one-pot methodology. Curcumin (Curc), a polyphenol with anti-tumoral activity, was loaded on the nanoparticles, and FA-targeted (Fe₃O₄@PEG@FA@Curc) and non-targeted (Fe₃O₄@PEG@Curc) systems were obtained. The internalization of Fe₃O₄@PEG@FA@Curc and Fe₃O₄@PEG@Curc nanoparticles was determined in two tumor cell lines, the FR-positive MCF-7 human breast carcinoma cell line and A549 human lung adenocarcinoma cell line, expressing a low level of FR. The results showed that MCF-7 cells internalize FA-functionalized nanoparticles to a greater extent than non-targeted ones and also than A549 cells. The competitive studies performed in the presence of FA in excess suggested that internalization is an FR-dependent process. The increased internalization of Fe₃O₄@PEG@FA@Curc nanoparticles in MCF-7 cells is correlated with increased cytotoxicity in this cell line compared to A549 cells. In conclusion, the FA-functionalized magnetic systems can ensure a better internalization of the nanoparticles and can be used to deliver various therapeutic agents, both in cancer treatment and also in the treatment of other inflammation-associated diseases such as rheumatoid arthritis, systemic lupus erythematosus, osteoarthritis, Crohn's disease or atherosclerosis.

Nanoscale Technologies in the Fight against COVID-19: From Innovative Nanomaterials to Computer-Aided Discovery of Potential Antiviral Plant-Derived Drugs

The last few years have increasingly emphasized the need to develop new active antiviral products obtained from artificial synthesis processes using nanomaterials, but also derived from natural matrices. At the same time, advanced computational approaches have found themselves fundamental in the repurposing of active therapeutics or for reducing the very long developing phases of new drugs discovery, which represents a real limitation, especially in the case of pandemics. The first part of the review is focused on the most innovative nanomaterials promising both in the field of therapeutic agents, as well as measures to control virus spread (i.e., innovative antiviral textiles). The second part of the review aims to show how computer-aided technologies can allow us to identify, in a rapid and therefore constantly updated way, plant-derived molecules (i.e., those included in terpenoids) potentially able to efficiently interact with SARS-CoV-2 cell penetration pathways.

Substituted Poly(Vinylphosphonate) Coatings of Magnetite Nanoparticles and Clusters

Magnetite nanoparticles and clusters of nanoparticles have been of Increasing scientific interest in the past decades. In order to prepare nanoparticles and clusters that are stable in suspension, different coatings have been used. Phosphates and phosphonates are a preferred anchoring group for the coating of magnetite nanomaterials. However, poly(vinylphosphonates) have rarely been used as a coating agent for any nanoparticles. Here, poly(methylvinylphosphonate) and other substituted polyvinylphosphonates are described as new coatings for magnetite nanoparticles and clusters. They show great stability in aqueous suspension. This is also the first time phosphonate-coated magnetite clusters have been synthesized in a one-pot polyol reaction. The coated magnetite nanoparticles and clusters have been characterized by TEM, EDX, FTIR, magnetization measurement, XRD as well as XPS. It has been shown that substituted vinylphosphonates can be easily synthesized in one-step procedures and as a polymeric coating can imbue important properties such as stability in suspension, tight binding to the particle surface, the ability to be further functionalized or to tightly adsorb metal ions. For the synthesis of magnetite clusters the cluster formation, polymerization and coating are done in a one-pot reaction and the resulting magnetite clusters show a higher amount of phosphonate coating than with a three-step procedure including a ligand exchange.

Iron Oxide Magnetic Nanoparticles with a Shell Made from Nanosilver-Synthesis Methodology and Characterization of Physicochemical and Biological Properties

The interest in magnetic nanoparticles is constantly growing, which is due to their unique properties, of which the most useful is the possibility of directing their movement via an external magnetic field. Thus, applications may be found for them as carriers in targeted drug delivery. These nanomaterials usually form a core in a core-shell structure, and a shell may be formed via various compounds. Here, nanosilver-shelled iron oxide magnetic nanoparticles were developed. Various reaction media and various Arabic gum (stabilizer) solution concentrations were investigated to verify those that were most beneficial one in limiting their agglomeration as much as possible. The essential oil of lavender was proposed as a component of such a medium; it was used alone or in combination with distilled water as a solvent of the stabilizer. The particle size was characterized by dynamic light scattering (DLS), the chemical structure was characterized via FT-IR spectroscopy, the crystallinity was characterized by X-ray diffraction (XRD), and the surface morphology and elemental composition were verified via the SEM-EDS technique. Moreover, UV-Vis spectrophotometry was used to verify the presence of the shell made of nanosilver. Importantly, the particles' pro-inflammatory activity and cytotoxicity towards L929 murine fibroblasts were also characterized. It was demonstrated that a 3% stabilizer solution provided a preparation of Fe₃O₄@Ag particles, but its stabilizing effect was not sufficient, as a suspension with micrometric particles was obtained; thus it was necessary to apply 4 h of sonication for their crushing. Next, the oil/water reaction medium was verified as beneficial in terms of nanoparticle formation. In such reaction conditions, the formation of particle agglomerates was strongly limited, and after 15 min of sonication a suspension containing only nanoparticles was obtained. The presence of a nanosilver shell was confirmed spectrophotometrically via XRD and SEM-EDS techniques. Importantly, the developed nanomaterials showed no cytotoxicity towards murine fibroblasts and no pro-inflammatory activity.

Dextran-Coated Iron Oxide Nanoparticles Loaded with Curcumin for Antimicrobial Therapies

The current trend in antimicrobial-agent development focuses on the use of natural compounds that limit the toxicity of conventional drugs and provide a potential solution to the antimicrobial resistance crisis. Curcumin represents a natural bioactive compound with well-known antimicrobial, anticancer, and antioxidant properties. However, its hydrophobicity considerably limits the possibility of body administration. Therefore, dextran-coated iron oxide nanoparticles can be used as efficient drug-delivery supports that could overcome this limitation. The iron oxide nanoparticles were synthesized through the microwave-assisted hydrothermal method by varying the treatment parameters (pressure and reaction time). The nanoparticles were subsequently coated with dextran and used for the loading of curcumin (in various concentrations). The drug-delivery systems were characterized through X-ray diffraction (XRD) coupled with Rietveld refinement, transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), selected area electron diffraction (SAED), dynamic light scattering (DLS) and zeta potential, thermogravimetry and differential scanning calorimetry (TG-DSC), vibrating sample magnetometry (VSM), and UV-Vis spectrophotometry, as well as regarding their antimicrobial efficiency and biocompatibility using the appropriate assays. The results demonstrate a promising antimicrobial efficiency, as well as an increased possibility of controlling the properties of the resulted nanosystems. Thus, the present study represents an important step forward toward the development of highly efficient antimicrobial drug-delivery systems.

An In Vitro and In Vivo Study of the Efficacy and Toxicity of Plant-Extract-Derived Silver Nanoparticles

Silver nanoparticles (AgNPs) display unique plasmonic and antimicrobial properties, enabling them to be helpful in various industrial and consumer products. However, previous studies showed that the commercially acquired silver nanoparticles exhibit toxicity even in small doses. Hence, it was imperative to determine suitable synthesis techniques that are the most economical and least toxic to the environment and biological entities. Silver nanoparticles were synthesized using plant extracts and their physico-chemical properties were studied. A time-dependent in vitro study using HEK-293 cells and a dose-dependent in vivo study using a Drosophila model helped us to determine the correct synthesis routes. Through biological analyses, we found that silver nanoparticles’ cytotoxicity and wound-healing capacity depended on size, shape, and colloidal stability. Interestingly, we observed that out of all the synthesized AgNPs, the ones derived from the turmeric extract displayed excellent wound-healing capacity in the in vitro study. Furthermore, the same NPs exhibited the least toxic effects in an in vivo study of ingestion of these NPs enriched food in Drosophila, which showed no climbing disability in flies, even at a very high dose (250 mg/L) for 10 days. We propose that stabilizing agents played a superior role in establishing the bio-interaction of nanoparticles. Our study reported here verified that turmeric-extract-derived AgNPs displayed biocompatibility while exhibiting the least cytotoxicity.

A Study of l-Lysine-Stabilized Iron Oxide Nanoparticles (IONPs) on Microalgae Biofilm Formation of Chlorella vulgaris

Despite iron-based nanoparticles gaining huge attraction in various field of sciences and technology, their application rises ecological concerns due to lack of studies on their interaction with microbial cells populations and communities, such as biofilms. In this study, Chlorella vulgaris cells were employed as a model of aquatic microalgae to investigate the impacts of l-lysine-coated iron oxide nanoparticles (lys@IONPs) on microalgal growth and biofilm formation. In this regard, C. vulgaris cells were exposed to different concentrations of lys@IONPs and the growth of cells was evaluated by OD600 and biofilm formation was analyzed using crystal violet staining throughout 12 days. It was revealed that low concentration of nanoparticles (< 400 µg/mL) can promote cell growth and biofilm formation. However, higher concentrations have an adverse effect on microalgal communities. It is interesting that microalgal growth and biofilm are concentration- and exposure time-dependent to lys@IONPs. Over long period (~ 12 days) exposure to high concentrations of nanoparticles, cells can adapt with the condition, so growth was raised and biofilm started to develop. Results of the present study could be considered in ecological issues and also bioprocesses using microalgal cells.

PEG-Functionalized Magnetite Nanoparticles for Modulation of Microbial Biofilms on Voice Prosthesis

This study reports the fabrication of nanostructured coatings based on magnetite, polyethyleneglycol, and biologically active molecule (polymyxin B-PM) for producing biofilm-resistant surfaces (voice prosthesis). Magnetite nanoparticles (MNPs) have been synthesized and functionalized using a co-precipitation method and were further deposited into thin coatings using the matrix-assisted pulsed laser evaporation (MAPLE) technique. The obtained nanoparticles and coatings were characterized by X-ray diffraction (XRD), thermogravimetric analysis with differential scanning calorimetry (TGA-DSC), scanning electron microscopy (SEM), transmission electron microscopy with selected area electron diffraction (TEM-SAED), Fourier-transform infrared spectroscopy (FT-IR), and infrared microscopy (IRM). Their antibiofilm activity was tested against relevant Staphylococcus aureus and Pseudomonas aeruginosa bacterial strains. The Fe₃O₄@PEG/PM surface of modified voice prosthesis sections reduced the number of CFU/mL up to four orders of magnitude in the case of S. aureus biofilm. A more significant inhibitory effect is noticed in the case of P. aeruginosa up to five folds. These results highlight the importance of new Fe₃O₄@PEG/PM in the biomedical field.

Antimicrobial Resistance and Inorganic Nanoparticles

Antibiotics are being less effective, which leads to high mortality in patients with infections and a high cost for the recovery of health, and the projections that are had for the future are not very encouraging which has led to consider antimicrobial resistance as a global health problem and to be the object of study by researchers. Although resistance to antibiotics occurs naturally, its appearance and spread have been increasing rapidly due to the inappropriate use of antibiotics in recent decades. A bacterium becomes resistant due to the transfer of genes encoding antibiotic resistance. Bacteria constantly mutate; therefore, their defense mechanisms mutate, as well. Nanotechnology plays a key role in antimicrobial resistance due to materials modified at the nanometer scale, allowing large numbers of molecules to assemble to have a dynamic interface. These nanomaterials act as carriers, and their design is mainly focused on introducing the temporal and spatial release of the payload of antibiotics. In addition, they generate new antimicrobial modalities for the bacteria, which are not capable of protecting themselves. So, nanoparticles are an adjunct mechanism to improve drug potency by reducing overall antibiotic exposure. These nanostructures can overcome cell barriers and deliver antibiotics to the cytoplasm to inhibit bacteria. This work aims to give a general vision between the antibiotics, the nanoparticles used as carriers, bacteria resistance, and the possible mechanisms that occur between them.