Preparation Of Iron Oxide Nanoparticles Research Articles

Application of Musa acuminata mediated iron oxide nanoparticles in the removal of sunset yellow dye

This study deals with the biogenic preparation of iron oxide nanoparticles (MION) by employing the Musa acuminata pseudostem extract. The morphological aspects of MION were investigated using SEM and HR-TEM, revealing its spherical shape and size of 20 - 60 nm. The MION’s XRD spectra further supported their size to be 20 nm. The FTIR spectrum depicted the presence of phytochemicals in Musa acuminata pseudo stem extract. Antibacterial studies were performed to assess MION’s biocompatibility. The MION was subjected to remove sunset yellow FCF dye solution and batch adsorption parameters like pH (3.0), contact time (180 min), MION dosage (4 mg/100 mL) and initial dye concentration (15 mg/L) were optimized. It was also ascertained that the Freundlich isotherm and pseudo-first-order kinetics were found to be best fit with a maximum adsorption capacity of 8.93 mg/mg, respectively. The thermodynamic findings indicated that MION's adsorption process exhibited spontaneity and endothermicity. The effect of ionic strength and humic acid resulted in a corresponding enhancement and reduction in the removal efficacy for sunset yellow adsorption. The recyclability of MION exhibited consistent performance over five successive cycles with a 75.4% sunset yellow recovery rate. Therefore, MION is cost-effective and efficient in removing toxic dye pollutants.

Thermal decomposition of acetylacetonates for highly reproducible synthesis of M-ferrite (Mn, Co and Zn) nanoparticles with tunable magnetic properties

In this work, we evaluated two synthetic approaches for the synthesis of M-ferrites nanoparticles, where M = Mn, Co, Zn with desired stoichiometric composition. As a starting point, thermal decomposition of acetylacetonates in benzyl alcohol and benzyl ether with oleic acid was chosen. Both of these approaches are widely used for the preparation of iron oxide nanoparticles; however, the synthesis of M-ferrites nanoparticles using these approaches is not well described. We have studied the influence of the nature of the solvent and surfactant on the quality of obtained ferrites (stoichiometric M:Fe ratio, structural phase analysis, morphology and core size of nanoparticles). It was shown that the chemical structure of solvent and presence of oleic acid plays a key role in controlling the nanoparticles stoichiometry. When benzyl alcohol was used as solvent, M-ferrites nanoparticles with diameters ranging from 3 to 5 nm were obtained, whereas of the benzyl ether with oleic acid resulted in formation of nanoparticles with diameters ranging from 7 to 9 nm. Moreover, only thermal decomposition of M acetylacetonates in benzyl alcohol was successful in obtaining M-ferrites nanoparticles with desired stoichiometry and high reproducibility M:Fe = 1:2 ± 0.1). In addition, magnetic properties of obtained nanoparticles have been studied at room temperature and their dependence on M:Fe ratio (1:2, 1:6, 1:10) was shown. The results show a superparamagnetic behavior for all synthesized samples and high magnetization values from 19.7 to 99.3 A•m2•kg−1. The maximum values of magnetization of M-ferrites samples are quite high for such small nanoparticles, which are closely related to their high crystallinity.

One-pot green synthesis of yttrium and zirconium doped iron oxide nanoparticles using Simarouba Glauca leaf extract

In this study, we have employed a green synthesis approach to prepare iron oxide nanoparticles doped with yttrium and zirconium using the extract of freshly plucked Simarouba Glauca (Paradise Tree) leaves. Very low dopant concentration is used to check the feasibility of doping even with very low dopant levels through green synthesis. The synthesized nanoparticles were characterized using techniques such as SEM, SEM-EDAX, HR-TEM, BF-TEM, TEM-EDS, XRD, FT-IR and UV–vis spectroscopy. Iron oxide nanoparticles and yttrium doped nanoparticles exhibited magnetism in the presence of an external magnetic field, and this is further supported by the drift observed in HR-TEM. The SEM-EDAX analyses verified the successful doping of 1.12 % (wt %) yttrium and 3.78 % (wt %) zirconium respectively in the doped nanoparticles. The average particle size of the synthesized nanoparticles falls within 100 nm. The XRD analyses indicate the hematite phase for the iron oxide nanoparticles, which is likely due to the high annealing temperature. This finding is verified through d-spacing calculation using HR-TEM. Yttrium and zirconium doped samples exhibited a variation in the bandgap, based on the Tauc plot obtained from the absorbance data. FTIR spectrum verified the presence of functionalities. Successful doping and changes in their optical and magnetic properties demonstrate their potential in various applications.

Synthesis of Imino Stabilized Iron Oxide Nanosensor for Selective Detection of Lead Ions

The present work describes the successful preparation of iron oxide nanoparticles (NSB1) stabilized with 4-((2-hydroxybenzylidene)amino)benzoic acid. The characterization has been achieved through ultraviolet visible (UV-Vis), fourier transform infra-red (FTIR) spectroscopy and scanning electron microscopy (SEM) with electron dispersive X-ray elemental analysis (EDX). These magnetic nanoparticles have exhibited significant chemosensing properties in the aqueous media to screen Cr3+, Cd2+, Li+, Co2+, Al3+, Pb2+, Ni2+ and Sr2+ ions. However, lead (Pb2+) ions have shown the highest selectivity as compared to other metal ions without any interference in the competitive ion study. The detection limit of Pb2+ ions was found to be 1.7 µM by this nanosensor. The binding ratio and stoichiometry was found to be 1:1 as measured by Job’s plot. The binding strength was also computed through Benesei-Hildebrand equation.

Study the Effect of Reaction Time on Preparation of Iron Oxide Nanoparticles by Hydrothermal Technique

In this research, a homemade autoclave reactor was used for preparing iron oxide nanoparticles by hydrothermal technique at different reaction times by using ferric chloride, ferrous sulfate, and ammonium hydroxide as raw materials. The XRD characterization showed that the nanoparticles of the samples have high crystallinity with the crystal phase of magnetite, furthermore, the crystal phase of hematite appears clearly as the reaction time increased. The SEM results showed when the time of reaction increased the average particle size increased too from 28.1 to 49.2 nm. That means the reaction time is an effective parameter for the nanoparticle's growth, The EDX spectrum verified the confirmation of iron oxide nanoparticles by the appearance of Iron and Oxygen peaks. The FT-IR results showed that all samples have an absorption peak at about 578 cm-1 corresponding to the Fe-O bond stretching modes of the in magnetite and the peak of hematite appeared as the reaction time increased above 2 hours which was confirmed with XRD results. Finally, the reaction time is a powerful tool for controlling in size and phase of nanoparticle preparation. Keywords: Hydrothermal, Iron Oxide, Reaction time, magnetite, and hematite.

Preparation and Characterization of Superparamagnetic Iron Oxide Nanoparticles (Fe3O4) for Biological Applications

Superparamagnetic iron oxide nanoparticles (SPIONs) are developed considering the importance of this class of in different fields of biochemical and biomedical applications owing to their distinctive chemical and physical properties. In this work, the preparation of iron oxide nanoparticles (SPIONs (using Co-precipitation method has been done as the most commonly used wet chemical method of magnetic nanoparticles preparation for biological applications. The SPIONs synthesis was based on sodium hydroxide (NaOH) mediated precipitation of Fe3+ and Fe2+ salts in an aqueous solution using trisodium citrate as surfactant within a closed system. The size and stability of the magnetite nanoparticles were carefully controlled using different chemical and physical parameters in order to obtain the SPIONs with small particle size and distribution that is needed for biomedical applications. The synthesized Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), and Zeta potential analysis (Zp). XRD pattern showed the presence of peaks corresponding to the phase of magnetite Fe3O4. Moreover, SEM and TEM results revealed spherical particles with a mean diameter of ≥ 5 nm. The monodispersed SPIONs were successfully prepared with a mean hydrodynamic size of 209.32 nm at a stirring speed of 900 rpm and NaOH concentration of 1.2 gm. The results showed that the particle size is considerably dependent on the stirring rate and NaOH concentration. Fe3O4 nanoparticles exhibited superparamagnetic behavior and the saturation magnetization was around 50 emu/g.

Preparation of iron oxide nanoparticles by banana peels extract and its usage in NDT

Plant extracts provide a great alternative to harmful chemicals, reproducible and cost effective. In this work, the iron oxide nanoparticles (Fe3O4-MNPs) were prepared through green route using banana peels extract (BPE). Morphological, structural and magnetic properties of the synthesized Fe3O4-BPE MNPs were characterized using SEM, EDS, Contact angle goniometer and Vibrating sample magnetometer (VSM). SEM analyses showed the presence of Fe3O4 and size ranging between 44 and 58 nm. VSM analysis exhibited that Fe3O4-BPE MNPs had soft magnetic properties. Fluorescein isothiocyanate (FITC) labeled Fe3O4-BPE MNPs were applied to the surface of the test bar, which has six artificial flaws at progressive depths between 1.29 and 3.33 mm from surface. Experiments were carried out using magnetic particle testing system at NDT Laboratory. The artificial flaws of 5 in depths between 1.29 and 2.31 mm from the surface were detected successfully.

Cellulose nanofibers/PVA blend polymeric beads containing in-situ prepared magnetic nanorods as dye pollutants adsorbents

Magnetic beads were developed from polyvinyl alcohol and different amounts of cellulose nanofibers (CNF) by in-situ preparation of iron oxide nanoparticles in an alkaline aqueous medium at room temperature. The CNF were isolated from wheat straw, whereas the magnetic nanoparticles (MNPs) precursors were simple iron salts. The complete characterization of all the obtained materials was conducted, and among some other outstanding results it showed that all the components were strongly interacting via hydrogen bonding, while the nano-rods and husks like MNPs were effectively acting as crosslinking dots. All the prepared materials had good magnetic responses, and they were able to remove not only cationic, but also anionic dye pollutants from aqueous model solutions.

Natural tannic acid (green tea) mediated synthesis of ethanol sensor based Fe3O4 nanoparticles: Investigation of structural, morphological, optical properties and colloidal stability for gas sensor application

A green tea mediated combustion synthesis route is implemented to prepare iron oxide nanoparticles. Chemical ferric nitrate and natural tannic acid extracted from green tea are used to prepare iron oxide nanoparticles, and the prepared sample is annealed at 350 °C. The crystal structure and phase of iron oxide nanoparticles have been analyzed using X-ray Diffraction (XRD). The crystallite size (D) and lattice constant (a) of the prepared and annealed samples are calculated. The mean crystallite size is found to be 23.4 nm for the prepared sample and 30.1 nm for the annealed sample. The morphological and compositional analysis are characterized through scanning electron microscopy (SEM) and EDX. The particle shape and size are recorded through tunneling electron microscopy (TEM) and the average grain size is 25 nm for as-prepared and 32 nm for annealed samples. The stability of colloidal systems of iron oxide nanoparticles has been assessed using the zeta potential. The as-prepared sample has a decent stability value of − 58.3 mV, whereas the annealed sample has an exceptional value of − 60.1 mV. The optical band gap of the samples is calculated from ultra-violet (UV–vis) spectra, and the energy band gap of the as-prepared samples is 2.24 eV, and the annealed sample is 2.78 eV. The gas sensing behavior of as-prepared and annealed iron oxide samples is analyzed for different aspects related to operating temperature, gas concentration, response-recovery time, and different gases.

Self-heating properties of iron oxide nanoparticles prepared at room temperature via ultrasonic-assisted co-precipitation process

ABSTRACT Preparation of iron oxide nanoparticles by a simple and environmentally friendly technique with high hyperthermia performance is highly desirable for biomedical application. These can potentially develop room temperature nanoparticles through the ultrasonic-assisted co-precipitation process. In this work, two types of iron oxide nanoparticles, un-coated iron oxide (IONPs) and coated iron oxide nanoparticles with tetraethoxysilane (IONPs-TEOS), were prepared at room temperature via ultrasonic-assisted co-precipitation process. The prepared nanoparticles were characterized using multiple techniques, such as Fourier transform infrared spectroscopy (FTIR), Thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), and X-ray diffraction (XRD). Self-heating properties and heating efficiency of the prepared nanoparticles were investigated under an alternative magnetic field in the function of carriers’ viscosity (water and ethanol) and induction time (0–6 minutes). It was found that the highest specific absorption rate (SAR) value for IONPs was 22.9 W/g when using water as a carrier. The viscosity affects the heating properties by changing the carrier through a Brownian mechanism and thus causes a significant SAR. Brownian relaxation is hindered by the particle’s hydrodynamic volume and the viscosity that tends to inhibit the particle rotation in the medium. Hence, the prepared room temperature iron oxide nanoparticles by this route can be applicable as hyperthermic agents for biomedical applications.

Preparation, characterization and some electrochemical study of waste derived iron Oxide-Carbon nanocomposite

Utilization of nanoparticles have seen significant growth as a filler material in different technological and product development. Iron oxide particles are found important due to their special characteristics such as; natural high abundance, low cost, robustness, low toxicity, high surface to volume ratio etc. The preparation of iron oxide nanoparticles using Wealth out of Waste (WoW) process is gaining much interest due to the economic point of view and environmental concern. In the current work, iron oxide nanoparticles with size 46 nm have been prepared by chemical method, using waste iron scrap obtained from mechanical lathe machines. Waste plastic and iron oxide nanoparticles, has been utilized in the pyrolysis process at 700 °C in a fixed bed pyrolysis reactor to prepare iron oxide–carbon composite. The electrochemical study of the composite was carried out and achieved specific capacitance to be 150 F/g and energy density to be 187.50 Wh/kg, which is comparable or even better than some other composite such as Fe3O4/CNT composite, Fe2O3 nanotube arrays, FeOOH rods and Fe3O4/CNF composite. The prepared Fe3O4-carbon composite is significant for reducing plastic waste, iron waste and providing low cost energy storage material.

Novel comparison of iron oxide nanoparticle preparation by mixing iron chloride with henna leaf extract with and without applied pulsed laser ablation for methylene blue degradation

Iron oxide nanoparticles (IONPs) were successfully prepared by mixing iron (III) chloride (FeCl3) salt with henna leaf extract using a simple chemical method with and without applied pulsed laser ablation (PLA) (Nd-YAG). It was found that the bio-molecules inside the henna leaves extract played a significant role in converting the iron salts into IONPs. The PLA technique affected the size, shape, purity, and phases of iron oxide NPs from Fe2O3 to FeO. Fe2O3 and FeO NPs play a crucial role in the removal of methylene blue (MB) dye in water treatment. IONPs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet (UV–vis), and photoluminescence (PL) spectroscopy. XRD results showed a small crystallite size (50 nm) with hexagonal structure (hematite) forFe2O3 NPs without using PLA, while for FeO NPs prepared by PLA, the crystallite size was smaller (24 nm) and the diffraction peaks indicated a cubic structure with excellent crystal quality. SEM showed the grain size of Fe2O3 NPs was approximately 69.92 nm, while for the FeO NPs, it was approximately 56.60 nm when PLA was applied. UV–vis measurements indicated a blue shift for the energy gap value from 2.75 eV for Fe2O3 NPs eV to 3.3 eV for FeO NPs. PL spectroscopy revealed the band edge emission was approximately 3.57 eV for Fe2O3 NPs without PLA, while the band edge emission exceeded 3.63 eV for FeO NPs with PLA application. Moreover, the photocatalytic activity of NPs was demonstrated by the degradation of MB dye under average light irradiation. The results indicate that the synthesized FeO NPs prepared by PLA exhibited higher degradation efficiency, reaching 95 % at 50 min with high photocatalytic activity than the Fe2O3 without PLA, for which the degradation efficiency was 88 % at 70 min.

Influence of channel height on mixing efficiency and synthesis of iron oxide nanoparticles using droplet-based microfluidics.

Microfluidic devices, allowing superior control over the spatial and temporal distribution of chemical substances and high process reproducibility, are nowadays essential in various research areas and industrial fields where the traditional “macroscopic” approach was no longer able to keep up with the increasing demands of high-end applications. In the present work, internal mixing of droplets formed by a flow-focusing X-junction at constant flow rates of both phases for three different channel heights (i.e. 20, 40 and 60 μm) was investigated and characterised. Both experimental methods and 3D CFD simulations were employed in order to resolve governing factors having an impact on internal mixing and homogenization time of model tracers inside of droplet reactors. Additionally, the influence of channel height on internal mixing was experimentally studied for continuous preparation of iron oxide nanoparticles by co-precipitation reaction. Since the initial nucleation phase is strongly affected by mixing and spatial distribution of all reactants, the final particle size and particle size distribution (PSD) can be used as direct indicators of mixing performance. It has been demonstrated that the smallest 20 μm channels provided narrower PSD and smaller particle mean size compared to higher channels.

The Preparation of Iron Oxide Nanoparticles by a Self-combustion Method

This paper deals with problematic of preparation of iron oxide nanoparticles according to a self-combustion method. Iron oxide nanoparticles can be used e.g. for catalysators and gas sensors or in MRI. The Self-combustion method is based on rapid chemical reaction between a fuel and iron oxide precursor. Glycine, urea and citric acid were used as fuels and iron nitrate nonahydrate was used as an iron oxide precursor. The self-combustion method doesn't require any special equipment, is environment-friendly due to minimize pollution and the results are easily reproducible. The shape, size, and phase of resulting particles were investigated studied using scanning electron microscopy and energy-dispersive analysis.

Ionic liquid-coated magnetic SiO2@Fe3O4 nanocomposite for temperature-assisted solid-phase extraction of venlafaxine

A temperature-assisted solid-phase extraction method was developed for the extraction of venlafaxine prior to its spectrofluorimetric determination. Ionic liquid modified Fe3O4 (IL@SiO2@Fe3O4) nanoparticles were prepared, characterized and used as the sorbent. A simple, one-step, rapid and nature-friendly method was used for the preparation of iron oxide nanoparticles using cinnamon extract. The synthesized Fe3O4 was characterized using X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The SEM images showed that the synthesized Fe3O4 nanoparticles have an approximately spherical structure with the sizes in the range of 30–60 nm. The synthesized Fe3O4 nanoparticles were coated with three ionic liquids: 1-butyl-3-methylimidazole hexafluorophosphate, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and ethyl-3- methylimidazolium ethyl-1 sulfate. The ionic liquid-coated magnetic nanoparticles were used for the extraction of venlafaxine from aqueous solutions. The highest extraction efficiency was obtained using 1-butyl-3-methylimidazole hexafluorophosphate-coated nanoparticles. The extracted venlafaxine was then determined spectrofluorimetrically at λex and λem of 261 and 301 nm, respectively. Under the optimal conditions, the relation between venlafaxine concentration and fluorescence intensity was linear in the range of 0.003–3.00 mg L−1 of the initial solution. The limit of detection for the determination of venlafaxine was found to be 0.001 mg L−1. The presented method was applied for the determination of venlafaxine in real samples with satisfactory results.

Nanomaterials Developed by Processing Iron Coordination Compounds for Biomedical Application

The iron oxides, widespread in nature, are used in numerous applications in practice due to their well-known properties. These properties can be modified by size lowering at nanoscale. Some applications, such as biomedical, require a rigorous selection of nanoparticles by size, shape, and surface functionality. In other applications, such as catalysis or magnetism, the composition (generally mixed oxides) and morphology of the nanoparticles are of high importance. The preparation of iron oxide nanoparticles (IONPs) is a complex process whose control raises a number of issues. The first challenge is finding the optimal experimental conditions, which would lead to the preparation of monodisperse nanoparticles. Another issue is the selection or setting a reproducible and clean manufacturing process without a need of complex purification. Even though at the moment several methods for preparing IONPs are known, there are still concerns in the scientific world to further improve existing methods or create new protocols. Therefore, the establishment of optimal methods for preparing IONPs with predetermined structural, dimensional, and morphological characteristics is an important task of scientists. Most of the methods reported in literature for the preparation of IONPs use proper metal salts as precursors. Recently, the use of the organometallic and coordination compounds of iron as precursors for IONPs has emerged as an alternative for a better control of these. Here, achievements reported in the literature in this direction are reviewed and critically analysed in relation to the conventional method based on iron salts.

Magnetic resonance imaging of stem cell-macrophage interactions with ferumoxytol and ferumoxytol-derived nanoparticles.

"Off the shelf" allogeneic stem cell transplants and stem cell nano-composites are being used for the treatment of degenerative bone diseases. However, major and minor histocompatibility antigens of therapeutic cell transplants can be recognized as foreign and lead to their rejection by the host immune system. If a host immune response is identified within the first week post-transplant, immune modulating therapies could be applied to prevent graft failure and support engraftment. Ferumoxytol (Feraheme™) is an FDA approved iron oxide nanoparticle preparation for the treatment of anemia in patients. Ferumoxytol can be used "off label" as an magnetic resonance (MR) contrast agent, as these nanoparticles provide measurable signal changes on magnetic resonance imaging (MRI). In this focused review article, we will discuss three methods to localize and identify innate immune responses to stem cell transplants using ferumoxytol-enhanced MRI, which are based on tracking stem cells, tracking macrophages or detecting mediators of cell death: (a) monitor MRI signal changes of ferumoxytol-labeled stem cells in the presence or absence of innate immune responses, (b) monitor influx of ferumoxytol-labeled macrophages into stem cell implants, and (c) monitor apoptosis of stem cell implants with caspase-3 activatable nanoparticles. These techniques can detect transplant failure at an early stage, when immune-modulating interventions can potentially preserve the viability of the cell transplants and thereby improve bone and cartilage repair outcomes. Approaches 1 and 2 are immediately translatable to clinical practice. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging Nanotechnology Approaches to Biology > Cells at the Nanoscale Diagnostic Tools > Biosensing.

Systemic exposure to a single dose of ferucarbotran aggravates neuroinflammation in a murine model of experimental autoimmune encephalomyelitis.

BackgroundMedicinal preparations of iron oxide nanoparticles (IONPs) have been used as MRI contrast agents for the diagnosis of hepatic tumors and the assessment of neuroinflammation and blood–brain barrier integrity. However, it remains mostly unclear whether exposure to IONPs affects neuroinflammation under disease conditions. The present study aims to investigate the impact of IONPs on autoimmune-mediated neuroinflammation using a murine model of experimental autoimmune encephalomyelitis (EAE) that mimics human multiple sclerosis.MethodsMice were either left untreated or immunized with myelin oligodendrocyte glyco-protein on day 0 followed by two injections of pertussis toxin for EAE induction. The EAE mice were intravenously administered with a single dose of the carboxydextran-coated IONPs, ferucarbotran (20 mg Fe/kg) and/or saline (as vehicle) on day 18. Symptoms of EAE were daily monitored until the mice were killed on day 30. Tissue sections of the brain and spinal cord were prepared for histopathological examinations. Iron deposition, neuron demyelination and inflammatory cell infiltration were examined using histochemical staining. The infiltration of microglial and T cells, and cytokine expression were examined by immunohistochemical staining and/or reverse transcription polymerase chain reaction (RT-PCR).ResultsIron deposition was detected in both the brain and spinal cord of EAE mice 3 days post-ferucarbotran treatment. The clinical and pathological scores of EAE, percentage of myelin loss and infiltration of inflammatory cells into the spinal cord were significantly deteriorated in EAE mice treated with ferucarbotran. Furthermore, ferucarbotran treatment increased the number of CD3+, Iba-1+, IL-6+, Iba-1+TNF-α+ and CD3+IFN-γ+ cells in the spinal cord of EAE mice.ConclusionA single exposure to ferucarbotran exacerbated neuroinflammation and disease severity of EAE, which might be attributed to the enhanced activation of microglia and T cells. These results demonstrated that the pro-inflammatory effect of ferucarbotran on the central nervous system is closely associated with the deterioration of autoimmunity.

Iron oxide nanoparticle preparation and its use for the removal of fluoride from aqueous solution: application of isotherm, kinetic and thermodynamics

Iron oxide nanoparticle preparation and its use for the removal of fluoride from aqueous solution: application of isotherm, kinetic and thermodynamics

Gram-Scale Preparation of Iron Oxide Nanoparticles with Renal Clearance Properties for Enhanced T1-Weighted Magnetic Resonance Imaging.

Extremely small-sized iron oxide nanoparticles (ESIONs) have been accepted as a potential alternative to gadolinium-based contrast agents for enhanced T1-weighted MR imaging. Recently developed zwitterion-coated ESIONs showed a high T1 contrast power and efficient renal clearing ability, but the tedious preparation steps that required high-cost, unfriendly experimental conditions and a sophisticated phase transition process would likely hinder their clinical translation. Herein, we present a one-pot gram-scale synthesis of zwitterion-capped ultrasmall iron oxide nanoparticles (ZUIONs). The nanoparticles have a core size as small as 3.7 nm and display high colloidal stability in various buffers. The r1 relaxivity of 2.4 mM-1 s-1 and r2/r1 ratio as low as 2.2 at 1.0 T guarantee their application as effective T1 MRI contrast agents. In vivo studies showed that ZUIONs could induce a significant contrast enhancement in blood pool and be eliminated from the body mainly through the renal excretion pathway. The combined advantageous features including facile preparation, excellent biocompatibility, strong T1 MRI contrast effect, appropriate circulation time, and renal clearable property would render ZUIONs attractive for practical applications.