Capped Iron Oxide Nanoparticles Research Articles

Influence of Different Capping Agents on the Structural, Optical, and Photocatalytic Degradation Efficiency of Magnetite (Fe3O4) Nanoparticles.

Octylamine (OTA), 1-dodecanethiol (DDT), and tri-n-octylphosphine (TOP) capped magnetite nanoparticles were prepared by co-precipitation method. Powder X-ray diffraction patterns confirmed inverse spinel crystalline phases for the as-prepared iron oxide nanoparticles. Transmission electron microscopic micrographs showed iron oxide nanoparticles with mean particle sizes of 2.1 nm for Fe3O4-OTA, 5.0 nm for Fe3O4-DDT, and 4.4 nm for Fe3O4-TOP. The energy bandgap of the iron oxide nanoparticles ranges from 2.25 eV to 2.76 eV. The iron oxide nanoparticles were used as photocatalysts for the degradation of methylene blue with an efficiency of 55.5%, 58.3%, and 66.7% for Fe3O4-OTA, Fe3O4-DDT, and Fe3O4-TOP, respectively, while for methyl orange the degradation efficiencies were 63.8%, 47.7%, and 74.1%, respectively. The results showed that tri-n-octylphosphine capped iron oxide nanoparticles are the most efficient iron oxide nano-photocatalysts for the degradation of both dyes. Scavenger studies show that electrons (e-) and hydroxy radicals (•OH) contribute significantly to the photocatalytic degradation reaction of both methylene blue and methyl orange using Fe3O4-TOP nanoparticles. The influence of the dye solution's pH on the photocatalytic reaction reveals that a pH of 10 is the optimum for methylene blue degradation, whereas a pH of 2 is best for methyl orange photocatalytic degradation using the as-prepared iron oxide nano-photocatalyst. Recyclability studies revealed that the iron oxide photocatalysts can be recycled three times without losing their photocatalytic activity.

Aromatic amine mediated ring opening of epoxides: A reaction catalyzed by biogenic iron oxide nanoparticles

An efficient green method was used for the synthesis of polyphenol capped iron oxide nanoparticles (ION) from an agro waste, peanut skin. The polyphenol capped ION was characterized by Fourier transformed infra-red (FTIR), Powder XRD and X-ray photoelectron spectroscopic (XPS) analysis. To evaluate the catalytic activities of ION, ring opening of epoxides by aromatic amines has been performed and the catalyst showed good activity with yields up to 90% of the major products using only 20 ​mg of the catalyst under solvent free neat condition at room temperature (28 ​°C) after 5 ​h. These nanoparticles can be reused for three times without significant loss in their activities.

Iron oxide nanoparticles conjugated curcumin to promote high therapeutic efficacy of curcumin against hepatocellular carcinoma

BackgroundCurcumin’s excellent conjugation capability with iron oxide nanoparticles plays a crucial role in enhancing both properties. Iron oxide, as a nanocarrier, will improve curcumin anticancer activity, while curcumin, as a capping agent, will minimize iron oxide nanoparticles toxicity and optimize their biomedical use. MethodologyCytotoxic and antioxidant effects of free curcumin (free Cur) and curcumin capped iron oxide nanoparticles (IONs@Cur) against human liver cancer cells (HepG2) were investigated in vitro. The genomic effect of free Cur and IONs@Cur on the expression of tumor suppressor gene (TP53), autophagy 4 (ATG-4), and superoxide dismutase (SOD2) genes were assessed using quantitative PCR (qPCR). ResultsIONs@Cur results showed significant cytotoxic effects against HepG2 cells, compared with free Cur, and the measured total antioxidant capacity (TAC) for HepG2 cells treated with IONs@Cur was superior to free Cur. Additionally, the treatment with IONs@Cur significantly upregulated the gene expression levels of SOD2 and TP53. Remarkably, the immunofluorescence staining of ATG-4 demonstrated that curcumin conjugation with IONs potentiated the cancer killing effect of curcumin via inducing autophagy. ConclusionThe promising iron oxide nanocarrier would greatly enhance curcumin anticancer activities against HepG2 cells.

Synthesis of gallotannin capped iron oxide nanoparticles and their broad spectrum biological applications.

Green synthesized nanoparticles (NPs) have attracted enormous attention for their clinical and non-clinical applications. A natural polyphenol, gallo-tannin (GT) was used to reduce and cap the Fe2O3-NPs. GT-Fe2O3-NPs were synthesized following co-precipitation of FeCl3 and FeSO4·7H2O with GT. Fe2O3-NPs absorbed light at 380 nm. Physicochemically, Fe2O3-NPs were spherical with slight aggregation and average diameter of 12.85 nm. X-ray diffraction confirmed crystallinity and EDX revealed the elemental percentage of iron and oxygen as 21.7% and 42.11%, respectively. FT-IR data confirmed the adsorption of gallo-tannin functional groups. Multiple drug-resistant (MDR) Escherichia coli (ESβL), Pseudomonas aeruginosa (ESβL), and Staphylococcus aureus were found susceptible to 500–1000 μg GT-Fe2O3-NPs per ml. In synergy, Fe2O3-NPs enhanced the efficiency of some antibiotics. GT-Fe2O3 NPs showed significant (P ≤ 0.05) inhibition of growth and biofilm against MDR E. coli, P. aeruginosa, and S. aureus causing morphological and biofilm destruction. Violacein production (quorum sensing mediated) by C. violaceum was inhibited by GT-Fe2O3-NPs in a concentration-dependent manner with a maximum decrease of 3.1-fold. A decrease of 11-fold and 2.32-fold in fungal mycelial growth and human breast cancer (MCF-7) cell viability, respectively was evident. This study suggests a plausible role of gallo-tannin capped Fe2O3-NPs as an alternative antibacterial, antiquorum sensing, antibiofilm, antifungal, and anti-proliferative agent.

The quest for reusability: The facile and stable immobilization of papain on cysteine functionalized iron oxide nanoparticles activated glass surface

The study displays the immobilization of papain on cysteine functionalized iron oxide nanoparticle coated glass beads. Glass beads were treated with (3-mercaptopropyl) trimethoxysilane and iron oxide nanoparticles capped with cysteine, to create a layer of cysteine on the surface of glass bead. This functionalized glass bead surface was further used to immobilize papain through glutaraldehyde treatment. The average size of cysteine capped iron oxide nanoparticles were found to be 50 nm. The binding of cysteine through the iron oxide nanoparticles was validated by Fourier transform infra-red spectroscopy. The activity of enzyme was found to be stable at variable temperature and pH conditions. The covalently immobilized enzyme on the glass bead sustained high enzyme activity and could be reused for 5 times without losing its activity. The immobilized papain retained 81% of its initial activity after 5 consecutive cycle. The storage stability analysis of the immobilized system revealed that it is stable for 6 months without loss in its activity. An average of 1.8 mg papain was successfully immobilized per gram of glass beads. In this case cysteine emerges as a new and effective medium for immobilizing biomolecules as it provides high efficiency towards immobilization.

Poly(acrylic acid) capped iron oxide nanoparticles via ligand exchange with antibacterial properties for biofilm applications

Biofilm infections pose a rising threat to public health due to its existing protective shield, which preventing biocide penetration. Here, the oleate-capped iron oxide nanoparticles (OIONPs) were synthesized by the high-temperature method first; after then, the poly(acrylic acid)-capped iron oxide nanoparticles (PIONPs) were obtained via a ligand exchange reaction between OIONPs and sodium poly(acrylic acid). The physicochemical properties of PIONPs were evaluated by Fourier-transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Transmission Electron Microscopy (STEM), Dynamic Light Scattering (DLS), and zeta potential. The FT-IR analysis confirmed the successful ligand exchange on the surface of iron oxide nanoparticles. STEM images displayed that the prepared PIONPs were monodisperse spherical nanoparticles. The PIONPs were stable in ultrapure water and could be kept for 5 weeks without aggregation. Next, Cell Counting Kit-8 (CCK-8) assay and fluorescent images confirmed the excellent cytocompatibility of PIONPs, while the iron concentration of PIONPs was in the range of 5∼120 mg/L. Finally, PIONPs exhibited efficient antibacterial activity against E. coli and S. aureus, and Staphylococcus aureus subsp. aureus Rosenbach (SASAR) biofilm could be destroyed by treating PIONPs under alternating current (AC) applied field conditions.

Oil-absorbent MnOx capped iron oxide nanoparticles: Synthesis, characterization and applications in oil recovery

In this study, we synthesized core-shell γ-Fe2O3/MnOx magnetic nanoparticles with core diameter of ~31 ± 3 nm and saturation magnetization ranging from 55 to 70 emu/g, using an inexpensive, facile and environmentally friendly approach. The synthesis is done through acid catalyzed reduction of KMnO4 and carboxymethyl cellulose (CMC) capped iron oxide in water. The synthesized particles were characterized by X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometer, Fourier transform infrared spectroscopy, thermo gravimetric analysis and differential scanning calorimeter. The continuous oxidation of carboxymethyl cellulose on Fe3O4 in the presence of KMnO4 enabled the formation of MnOx shell. The thickness of MnOx shell is tuned by varying the amount of acid and the ratio of KMnO4: iron oxide precursor. The shell thickness increased from ~2.9 nm to 4.6 nm with increase in HCl concentration because of rapid formation of large number of nuclei and their deposition on iron oxide. Interestingly, MnOx shell was amorphous at lower [H+] but was crystalline at higher [H+]. The magnetic particles with amorphous MnOx nanoshell showed superior stability for a range of pH. A change in particle morphology is (flower to square shaped) due to the competitive adsorption of oxidized organic products of carboxymethyl cellulose polymer and MnOx nuclei at higher temperature, and the higher Gibbs free energy of the flower shaped particles. XPS results show that the iron oxide coated with CMC has 2:3 relative concentration of the Fe2+:Fe3+ ions, while oxidation state of Fe in MnOx capped one was +3. The percentage of hydroxyl group content decreased from 14 to 11% when the Fe3O4:KMnO4 ratio was changed from 1:0.2 to 1:0.5 due to the change in Mn3+:Mn4+ ratio. It is hypothesized that oil sorption occur through exchange of surface hydroxyl groups on MnOx shell. The oil removal efficiency of the prepared particle was >93% after six cycles.

Effect of synthetic conditions on the crystallinity, porosity and magnetic properties of gluconic acid capped iron oxide nanoparticles

Magnetic iron oxide nanoparticles are essential materials for the molecular separation process, catalysis, drug-delivery and water remediation. In this paper, the effect of synthesis conditions on the characteristic crystallinity, porosity and magnetic properties of gluconic acid capped iron oxide nanoparticles were evaluated. The iron oxide nanomaterials were synthesized using the coprecipitation method and characterized using Fourier Transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), x-ray diffraction (XRD), superconducting quantum interference device (SQUID) and Brunauer–Emmett–Teller (BET) techniques. The SQUID results showed that the as-synthesized nanomaterials possessed both paramagnetic and superparamagnetic properties with saturation magnetization (Ms) values ranging between 1.49 and 2.69 emu/g. Textural analysis revealed that the nanomaterials were mesoporous in nature with Type II isotherm and H3 hysteresis loop and Type IV isotherm with H2 hysteresis loop respectively. XRD analyses showed the nanomaterials to be maghemites and haematite with average crystallite sizes ranging from 10.85 to 16.27 nm. Also, the nanomaterials exhibited high surface areas ranging from 158.54 to 353.80 m2/g and pore size ranged between 3.33 and 5.54 nm. This information suggests that iron oxide nanomaterials with different porosity, crystallinity, and magnetic properties may be obtained by varying the synthesis conditions.

Green synthesis of near-infrared absorbing eugenate capped iron oxide nanoparticles for photothermal application

Nanomaterials exhibit different interesting physical, chemical, electronic and magnetic properties that can be used in a variety of biomedical applications such as molecular imaging, cancer therapy, biosensing, and targeted drug delivery. Among various types of nanoparticles, super paramagnetic iron oxide nanoparticles (SPIONs) have emerged as exogenous contrast agents for in vitro and in vivo deep tissue imaging. Here, we propose a facile, rapid, non-toxic, and cost-effective single step green synthesis method to fabricate eugenate (4-allyl-2-methoxyphenolate) capped iron oxide nanoparticles (E-capped IONPs). The magnetic E-capped IONPs are first time synthesized using a medicinal aromatic plant, Pimenta dioica. The Pimenta dioica leaf extract was used as a natural reducing agent for E-capped IONPs synthesis. The crystalline structure and size of the synthesized spherical nanoparticles were confirmed using the x-ray diffraction and electron microscopic images respectively. In addition, the presence of the functional groups, responsible for capping and stabilizing the synthesized nanoparticles, were identified by the Fourier transform infra-red spectrum. These nanoparticles were found to be safe for human cervical cancer (HeLa) and human embryonic kidney 293 (HEK 293) cell lines and their safety was established using MTT[3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide] assay. These green synthesized E-capped IONPs display a distinct absorbance in the tissue transparent near-infrared (NIR) wavelength region. This property was used for the NIR photothermal application of E-capped IONPs. The results suggest that these E-capped IONPs could be used for deep tissue photothermal therapy along with its application as an exogenous contrast agent in biomedical imaging.

Treatment of breast cancer with capped magnetic-NPs induced hyperthermia therapy

Treatment for different diseases has been revolutionized dramatically due to the advancements in the medical sciences, such as the practice of capped nanoparticles to treat carcinoma could be a promising strategy for future. For the first time we show that capping agents enhance the magnetization power while simultaneously reduce the particles size as well. Different capped iron oxide nanoparticles (Fe3O4-NPs) were synthesized using different organic ligands viz. citric acid and malic acid through co-precipitation method. Compared with un-capped particles, the capped-NPs exhibited reduction in size and cubic spinal structure as confirmed by TEM images and XRD peaks. Moreover, SEM images revealed that the organic acid functionalized NPs had irregular geometries in comparison with uncapped NPs. The presence of -OH -CH2 and –COOH groups were confirmed by FTIR and variations in magnetic field were recorded using VSM. For in vivo bioassay, capped magnetic NPs were injected inside tumor cells followed by exposure to alternating magnetic fields. Exposure to alternating magnetic field of 15 mT and frequency 100 kHz for 1 h caused rise in temperature from 37 to 48 °C and also resulted in cellular damage and subsequent apoptotic cell death. In an overall assessment, functionalized Fe3O4-NPs exhibited reduction in particle size, increased magnetization properties and enhanced efficacy for carcinoma treatments by hyperthermia.

Long-term biodistribution and toxicity of curcumin capped iron oxide nanoparticles after single-dose administration in mice

AimIn this study, in vivo biodistribution, clearness and toxicity of curcumin capped iron oxide nanoparticles (Cur-IONPs) were addressed in different body organs. Materials and methodsThe physicochemical properties of the prepared Cur-IONPs were investigated. Long term (3 weeks) biodistribution, clearness and toxicity were assessed for a single-dose administration of Cur-IONPs (5 mg/kg). The iron content in liver, kidney, spleen and brain was quantified using atomic absorption spectroscopy. Serum biochemical parameters were also measured. Key findingsThe integrated in vivo results demonstrated that Cur-IONPs was mostly taken up in the liver and spleen reaching its highest levels on days 1 and 2, respectively. In the brain, the results showed significant accumulation of Cur-IONPs between 1 h to 1-day post injection. This represented the successful penetration Cur-IONPs across the blood-brain barrier. Serum biochemical analysis demonstrated a temporal disturbance in the performance of body organs. Also, the body weights showed no alteration throughout the experiment. SignificanceIt has been deduced that the promising green synthesized Cur-IONPs as an “All in One” nanoplatform is safe enough to be used in diagnostic and therapeutic purposes.

An efficient protocol to use iron oxide nanoparticles in microfluidic paper device for arsenic detection

This method describes a rapid ecofriendly and affordable method for detecting arsenic in the water sample. The system designed works on the principle that involves generation of arsine due to reduction of arsenic by bare and cysteine capped iron oxide nanoparticles and its further reaction with silver nitrate present on the microfluidic paper analytical device (µPAD). Change in the color of µPAD from colorless to reddish brown is a result of reaction between arsine gas and silver nitrate, and is the detection criteria. The sample solution of arsenic was prepared in lemon juice to provide the required acidic environment for hydride generation. This proposed method has detection limit of 0.01?ppm (10?ppb) and 1?ppm for cysteine capped and bare iron oxide nanoparticles respectively. This is for the first time that iron oxide nanoparticles are being used for detection and reduction arsenic species in environmental sample. The same device can be used for on-site detection in an ecofriendly manner.

Ethylenediaminetetraacetic acid capped superparamagnetic iron oxide (Fe3O4) nanoparticles: A novel preparation method and characterization

A novel and facile strategy is introduced for the preparation of ethylenediaminetetraacetic acid (EDTA) capped magnetite nanoparticles (MNPs). In this strategy, Fe3O4 nanoparticles were electrodeposited from a deposition bath containing 0.005M Fe2+/Fe3+ nitrate and chlorides alts and 1g/L EDTA. A simple deposition mode i.e. constant current and two-electrode set-up was used in the electro-synthesis procedure. The magnetite phase of the deposited nanoparticles was confirmed through XRD and FT-IR analyses. Morphological observations through FE-SEM and TEM confirmed the formation of spherical MNP particles with an average size of 10nm. The EDTA layer on the surface of the electro-synthesized magnetite nanoparticles was proved based on FT-IR, DLS and TG data. Vibrating sample magnetometer (VSM) measurements confirmed the EDTA capped iron oxide nanoparticles to have a super-paramagnetic nature, since they exhibit a high saturation magnetization (Ms=51.9emug−1), as well as, negligible remnant magnetization (Mr=0.59emug−1) and coercivity (Hc=0.85Oe). Based on the obtained results, the proposed platform can be considered as a fast, simple and efficient method for the preparation of the EDTA capped magnetite nanoparticles.

Antibacterial activity of biochemically capped iron oxide nanoparticles: A view towards green chemistry

A green approach to fabricate nanoparticles has been evolved as a revolutionary discipline. Eco-compatible reaction set ups, use of non-toxic materials and production of highly active biological and photocatalytic products are few benefits of this greener approach. Here, we introduce a green method to synthesize Fe oxide NPs using Punica granatum peel extract. The formation of Fe oxide NPs was optimized using different concentrations of peel extract (20mL, 40mL and 60mL) to achieve small size and better morphology. The results indicate that the FeNPs, obtained using 40mL concentration of peel extract possess the smallest size. The morphology, size and crystallinity of NPs was confirmed by implementing various techniques i.e. UV–Vis spectroscopy, X-ray diffraction, Scanning Electron Microscopy and Electron Diffraction Spectroscopy. The bio-chemicals responsible for reduction and stabilization of FeNPs were confirmed by FT-IR analysis. The biogenic FeNPs were tested for their size dependent antibacterial activity. The biogenic FeNPs prepared in 40mL extract concentrations exhibited strongest antibacterial activity against Pseudomonas aeruginosa i.e. 22 (±0.5) mm than FeNPs with 20mL and 60mL extract concentrations i.e. 18 (±0.4) mm and 14 (±0.3) mm respectively. The optimized FeNPs with 40mL peel extract are not only highly active for ROS generation but also show no hemolytic activity. Thus, FeNPs synthesized using the greener approach are found to have high antibacterial activity along with biocompatibility. This high antibacterial activity can be referred to small size and large surface area.

Terephthalic acid capped iron oxide nanoparticles for sensitive electrochemical detection of heavy metal ions in water

This work describes a simple wet chemical synthesis of iron oxide (Fe3O4) nanoparticles (NPs) capped with terephthalic acid (TA) and their application for the individual detection of Hg(II), Pb(II) and Cd(II) ions as well as simultaneous and selective detection of Hg(II), Pb(II) and Cd(II) ions by electrochemical approach. Terephthalic acid capped Fe3O4 NPs were first characterized by cyclic voltammetry (CV) using redox couples Fe(CN)63−/4−, thereafter square wave anodic stripping voltammetry (SWASV) was utilized for the detection of Hg(II), Pb(II) and Cd(II) ions. Optimization of experimental parameters such as deposition time, deposition potential and pH value of the electrolyte towards electrochemical detection of target heavy metal ions was also carried out in SWASV method. Under optimized experimental conditions limit of detection (LOD) values for individual analysis of Hg(II), Pb(II) and Cd(II) ions were found to be 0.1, 0.05μM and 0.01μM respectively, whereas the LOD values for the simultaneous analysis of Hg(II), Pb(II) and Cd(II) ions were found to be 0.3μM, 0.04μM and 0.2μM respectively.

Citric Acid Capped Iron Oxide Nanoparticles as an Effective MALDI Matrix for Polymers.

A new matrix-assisted laser desorption ionization (MALDI) mass spectrometry matrix is proposed for molecular mass determination of polymers. This matrix contains an iron oxide nanoparticle (NP) core with citric acid (CA) molecules covalently bound to the surface. With the assistance of additives, the particulate nature of NPs allows the matrix to mix uniformly with polar or nonpolar polymer layers and promotes ionization, which may simplify matrix selection and sample preparation procedures. Several distinctively different polymer classes (polyethyleneglycol (PEG), polywax/polyethylene, perfluoropolyether, and polydimethylsiloxane) are effectively detected by the water or methanol dispersed NPCA matrix with NaCl, NaOH, LiOH, or AgNO3 as additives. Furtheremore, successful quantitative measurements of PEG1000 using polypropylene glycol 1000 as an internal standard are demonstrated. Graphical Abstract ᅟ.

Electrochemical immunosensor based on PEG capped iron oxide nanoparticles

In this study, we have synthesized polyethylene glycol (PEG) capped iron oxide (Fe3O4) nanoparticles by chemical co-precipitation method. These PEG-Fe3O4 NPs and bare Fe3O4 NPs have been characterized using different techniques such as X-ray diffraction, transmission electron microscope, dynamic light scattering, Fourier transform infra-red spectroscopy, and electrophoresis technique. These PEG-Fe3O4 NPs were deposited onto indium tin oxide (ITO) coated glass substrate by electrophoretic deposition technique and further functionalized with the monoclonal antibodies (Ab) specific to Vibrio cholerae toxin and bovine serum albumin (BSA) using EDC-NHS chemistry. The functionalization of PEG-Fe3O4/ITO electrode with Ab and BSA confirmed, by a change in IR spectra. The electrochemical studies revealed that the PEG-Fe3O4/ITO electrode provides heterogeneous electron transfer rate as 0.342s−1, higher active surface area of 1.5mm2 and provide excellent microenvironment for the entrapment of Ab and BSA. This BSA/Ab/PEG-Fe3O4/ITO immunoelectrode provides excellent sensitivity (99.6Ω/ng1mL−1cm−2) and low detection limit (0.5ngmL−1) as compared to other capping agents.

EDTA capped iron oxide nanoparticles magnetic micelles: drug delivery vehicle for treatment of chronic myeloid leukemia and T1–T2 dual contrast agent for magnetic resonance imaging

This study shows that multiple functionalities like drug delivery and T1–T2 dual modalities can be achieved by a proper surface architecture.

Enhanced anion sensing by γ-irradiated polyphenol capped iron oxide nanoparticles

A novel method was designed for the synthesis of polyphenol capped amorphous iron oxide nanoparticles (ION) using an agro waste (peanut skin). The synthesized nanoparticles were characterized by absorption spectroscopy, TEM, SEM, IR, Raman and XRD. An increased rate of formation of the nanoparticles is observed upon low dose gamma irradiation. ION shows specific spectral features with perchlorate anion even in presence of other anions selected for the anion sensing study. The nanoparticles formed in presence of irradiation was found even more sensitive to lower concentration of perchlorate owing to its finely dispersed nature and increased surface area.

A smart method for the fast and low-cost removal of biogenic amines from beverages by means of iron oxide nanoparticles

Silica capped iron oxide nanoparticles are used to bind biogenic amines dissolved in a wine sample. The adduct formed by the capped paramagnetic nanoparticles and amines is separated by a weak magnetic field without affecting the wine taste.