Open access peer-reviewed chapter

New Approaches in Synthesis and Characterization Methods of Iron Oxide Nanoparticles

Written By

Cristina Chircov and Bogdan Stefan Vasile

Submitted: 20 November 2021 Reviewed: 26 November 2021 Published: 05 January 2022

DOI: 10.5772/intechopen.101784

From the Edited Volume

Iron Oxide Nanoparticles

Edited by Xiao-Lan Huang

Chapter metrics overview

575 Chapter Downloads

View Full Metrics

Abstract

Recent years have witnessed an extensive application of iron oxide nanoparticles within a wide variety of fields, including drug delivery, hyperthermia, biosensing, theranostics, and cell and molecular separation. Consequently, synthesis and characterization methods have continuously evolved to provide the possibility for controlling the physico-chemical and biological properties of the nanoparticles to better suit the envisaged applications. In this manner, this chapter aims to provide an extensive overview of the most recent progress made within the processes of iron oxide nanoparticle synthesis and characterization. Thus, the chapter will focus on novel and advanced approaches reported in the literature for obtaining standardized nanoparticles with controllable properties and effects. Specifically, it will emphasize the most recent progress made within the microwave-assisted, microfluidics, and green synthesis methods, as they have shown higher capacities of controlling the outcome nanoparticle properties.

Keywords

  • iron oxide nanoparticles
  • synthesis processes
  • green synthesis processes
  • characterization techniques
  • physico-chemical properties

1. Introduction

Iron oxides are transition metal oxides ubiquitously found in nature, having many implications in various biological and geological processes [1, 2, 3, 4]. They occur naturally as aggregates, mineral nanoparticles, or nanostructured coatings onto other soil grains [5], being an essential biogeochemically-active component of the Earth ecosystem [6]. Moreover, iron oxides are formed in a variety of polymorphs with different stoichiometric and crystalline structures [2, 3, 7], including oxides, e.g., wüstite or ferrous oxide (FeO), magnetite (Fe3O4 or FeO·Fe2O3), maghemite (γ-Fe2O3), ε-Fe2O3, hematite (α-Fe2O3), and β-Fe2O3, hydroxides, e.g., iron(III) hydroxide (bernalite) and iron(II) hydroxide, and oxyhydroxydes, e.g., goethite, feroxyhyte, akaganeite, and lepidocrocite [2, 3, 7, 8, 9, 10, 11, 12, 13]. Among them, magnetite, maghemite, and hematite are crystalline and most commonly used in biomedical and pharmaceutical applications, while other forms, such as goethite, are amorphous and occur at high pressure and temperature conditions [2, 3, 7, 14]. Furthermore, iron oxides can also be categorized based on their electrical properties into insulative, i.e., ferrous oxide, conductive, i.e., magnetite, and semiconductive, i.e., hematite and goethite [1].

By contrast, iron oxides can be processed into nanoparticles with magnetic properties, which further allow for their manipulation by external magnetic fields [7, 15]. Among them, magnetite nanoparticles are, by far, the most intensively studied, as they have demonstrated considerable potential in a myriad of applications, including drug delivery, magnetofection, hyperthermia, photoablation therapy, magnetic resonance imaging as contrast enhancement agents, theranostics, biosensing, bioanalysis through biological labeling, tracking, and detection, bioseparation, antimicrobial therapies, tissue engineering and regeneration, wound healing, catalysis, nanorobots, ferrofluids, microelectronics and ultrahigh density magnetic storage media, magnetic paints, pollutant removal sorbents, and batteries [7, 16, 17, 18, 19, 20, 21, 22]. Additionally, recent studies have shown an intrinsic peroxidase activity of iron oxide nanoparticles, which could be further exploited in applications such as biocatalysis, wastewater treatment, detection tools, magnetic enzyme-linked immunosorbent assay kits, or artificial enzymes [23, 24, 25, 26, 27, 28, 29].

Evidently, each of the previously mentioned applications require specific nanoparticle properties [30]. In this context, it has been confirmed that the physico-chemical properties of magnetite nanoparticles, namely, size, shape, stability, crystal structure and crystallinity, chemical composition, and surface area, energy, and roughness, significantly determine their magnetic properties and, consequently, their biological behavior, drug concentration, toxicity, and efficacy [19, 31, 32, 33]. Moreover, studies have shown that the synthesis route of magnetite nanoparticles greatly impacts their physico-chemical properties, thus highlighting the necessity to improve synthesis performance by enhancing standardization, automation, monitoring, and mass production [17, 19, 33].

Presently, the most ubiquitous synthesis method for magnetite nanoparticles is the co-precipitation of ferrous and ferric ions through the addition of an alkaline solution [34]. Although it is a simple and cost-efficient method characterized by considerably high productivity [32], its reproducibility is still limited due to the presence of the intermediate phases within the final product. Additionally, it does not allow for the precise control of nanoparticle size and shape, which further leads to significant variations in the physico-chemical properties of the final product [32, 34, 35, 36]. Therefore, there is a fundamental need for the exploration of novel synthesis processes that could further ensure optimal, controllable, and scalable properties. In this context, iron oxide nanoparticles obtained from natural, green sources are continuously gaining the interest of the scientific community as they provide a potential alternative to overcome the limitations of conventional nanoparticles [37]. Consequently, characterization techniques should also be advanced to ensure a reliable assessment of nanoparticle properties. In this manner, the variety of magnetic nanoparticle applications, ranging from biomedicine and pharmaceutical industry to data storage, could greatly benefit from such improvements.

Therefore, this chapter aims to provide an updated overview of the most recent developments within the field of magnetite nanoparticle synthesis and processing, as well as the most advanced characterization techniques utilized for evaluating their properties and potential.

Advertisement

2. Novel iron oxide nanoparticles synthesis methods

There are two well-established approaches involved in the synthesis of nanoparticles, namely, top-down and bottom-up approaches. Generally, top-down methods involve the crushing, breaking, or fractioning of bulk materials into smaller parts to produce nanoparticles through mechanical action [38, 39]. Such methods include mechanical crushing, milling, or grinding, laser ablation, sputtering, etching, or electron beam deposition, offering an alternative eco-friendly route despite the required high time and power consumption [40, 41, 42]. By contrast, bottom-up approaches are based on chemical reactions among specific atoms, ions, or molecules necessary for the formation of nanoparticles. Considering these principles, synthesis routes can be further divided based on the nature of the involved process into physical, that can be associated to the top-down methods, chemical (e.g., co-precipitation, sol-gel, thermal decomposition, emulsion and microemulsion, hydrothermal, and microwave-assisted methods), and biological (which utilize plants or microorganisms for the generation of nanoparticles), the latter two being attributed to bottom-up approaches (Figure 1) [38, 39, 43, 44].

Figure 1.

The main types of magnetite nanoparticle synthesis methods. Reprinted from an open-access source [43].

Figure 2 depicts a comparison between the most commonly used methods for the synthesis of magnetite nanoparticles. It can be observed that chemical methods comprise the majority of the investigated routes, the co-precipitation method accounting for the highest percentage. Specifically, the co-precipitation process involves two possible pathways, either partial oxidation of iron(II) salts or the aging of a stoichiometric mixture of iron(III) and iron(II) salts through the addition of an alkaline solution that leads to nucleation and growth mechanisms and finally to the generation of Fe3O4 nanoparticles. The chemical reaction principle involved in the production of magnetite nanoparticles is shown in Eq. (1):

Figure 2.

The prevalence of the most commonly utilized magnetite nanoparticle synthesis methods. Reprinted from an open-access source [45].

Fe2++2Fe3++8OHFeOH2+2FeOH3Fe3O4+4H2O.E1

Although it is the easiest to implement, time-efficient, and safe method, involving limited use of harmful solvents, the co-precipitation process is considerably disadvantageous in terms of reproducibility and possibility to control the outcome properties of the obtained nanoparticles [46, 47].

Thus, there is a fundamental need for the investigation of novel synthesis routes that could improve the features of magnetite nanoparticles. In this context, recent years have witnessed a shift toward the implementation of previously non-conventional methods that could potentially provide a plethora of alternatives in terms of modulating physico-chemical properties. Thus, the following sections will describe the most recent advancements within the production of magnetite nanoparticles through microwave-assisted, microfluidic, and green synthesis methods.

2.1 Microwave-assisted method

Owing to its numerous advantages, microwave-assisted synthesis has become a particularly attractive method for various synthetic chemistry reactions. Specifically, this technique has provided the means for the easy production of nanoparticles in a considerably time- and cost-efficient manner, with reduced energy consumption and increased environmental friendliness [48, 49, 50, 51] through the use of 50% less power than electric furnaces with similar capacities [52]. Besides the associated economic aspects, the microwave-assisted method has received increased scientific interest due to the possibility of tuning the parameters to obtain the desired size and shape of magnetite nanoparticles with significantly narrow distributions and high reproducibility, phase purity, and yield [49, 50, 51]. This is possible due to the characteristic uniform heating and nucleation, rapid kinetics and crystallization, and phase selectivity [50, 51].

The basic principle involved in this method is based on the activation and subsequent alignment of dipoles (i.e., mechanism of dipolar polarization) and/or ions (i.e., mechanism of ionic conduction) present within a material through the interactions with microwave electromagnetic radiations. Consequently, internal heating will occur in a highly homogenous manner, thus, leading to a rapid temperature rise that is responsible for reducing the reaction time and the necessary energy [48, 49, 50, 51, 52]. In the case of magnetite nanoparticles, it has been demonstrated that the microwave-assisted method offers the possibility to control their magnetic properties by adjusting the experimental parameters [49].

Generally, the microwave-assisted method is combined with other synthesis processes, such as co-precipitation. Thus, the synthesis involves the co-precipitation of iron oxide nanoparticles through the classical method, followed by the microwave treatment that enables the control over the properties of the nanoparticles. Several studies have demonstrated the possibility to obtain monodisperse iron oxide nanoparticles with well-controlled sizes and high crystallinity, saturation magnetizations, and stability, as compared to the co-precipitation counterparts [53, 54, 55, 56]. Additionally, the possibility of developing uniform polyethylene glycol [53], humate polyanion [54], and silica [55] coatings was also demonstrated.

2.2 Microfluidic approaches

Microfluidics is a relatively new field that has brought together fluid dynamics, chemistry, and material science principles for allowing the precise and accurate manipulation of small fluid volumes within microchannels [57, 58]. In this context, microfluidic technology-based methods for the synthesis of nanomaterials have emerged as an alternative to conventional routes that could provide possible solutions to the currently existing limitations. Specifically, microfluidic devices represent synthesis platforms with outstanding features for the fabrication of nanoparticles, including small capillary dimensions and consequent large surface/volume ratios and reduced reagent volume use, rapid and uniform mass and heat transfer, ease of automation, reduced residence time, and precise control of mixing [38, 57, 58, 59]. In this manner, by increasing the control of the implicated reaction parameters (e.g., device geometry, flow rate, reagent concentration, reaction time, temperature) [59, 60], nanoparticles with superior uniformity, stability, and encapsulation efficiency and narrow particle size distributions can be obtained in a highly reproducible and controllable manner [38, 57, 58, 59, 60].

Based on their geometry, microfluidic devices can be classified into tubular reactors, which generally involve circular channels that are either in-house produced or purchased (most common commercially available reactors have T and Y type junctions), and chip reactors, which involve more complex geometries and are usually in-house manufactured using various fabrication techniques [38]. The working principle of microfluidic approaches for the synthesis of nanoparticles resides on the movement of fluids within microchannels and microchambers with unique geometries to integrate the preparation, reaction, and separation steps. In this context, there are two main types of microfluidic reactors that involve different synthesis strategies, namely, single-phase or continuous-flow microfluidics and multi-phase or droplet-based microfluidics, which can be further divided according to the carrier fluid into gas–liquid and liquid–liquid segmented flows [38, 59].

Microfluidics is currently evolving as a promising alternative for the synthesis of magnetite nanoparticles with controlled size, shape, and surface chemistry that can be modulated according to the application requirements [57, 58]. Since it involves a relatively simple reaction, it can be obtained through both types of synthesis strategies. Continuous-flow microreactors that contain one inlet for the iron precursor solution and one inlet for the alkaline solution will ensure the formation of the nanoparticles at the interface between the two fluid layers if the pH value is high enough for nucleation. While this is usually the preferred route owing to its increased homogeneity and versatility, some applications require faster interactions. Therefore, the multiphase microfluidics involving cross-flow designs are receiving increasing attention. In this approach, the channels containing the precursor solutions, i.e., the dispersed phase, will intersect the channels containing the alkaline solution, i.e., the continuous phase, where the nanoparticles will form and be further transported within the continuous phase [38, 60]. Furthermore, the microfluidic platforms used for the synthesis of magnetite nanoparticles can be made of various materials, such as glass, metals, silicon, or polymers, that must be resistant to the fluids introduced within the microchannels [38].

Although the number of studies is still limited, the results are promising, thus paving the way toward the future of nanoparticle synthesis. In this context, the synthesis of magnetite nanoparticles was investigated through the use of a single-flow polydimethylsiloxane microfluidic reactor [61] and a T-junction polymethylmethacrylate microchip fabricated by a laser cutting machine [57]. Furthermore, another study fabricated magnetite nanoparticles using a 3D flow microfluidic device focused by two basic sheath streams, that were subjected to a postsynthesis surface functionalization step outside the microreactor [62]. Moreover, other studies demonstrated the possibility of developing in situ chitosan-coated magnetite nanoparticles using two types of microchip configurations fabricated through 3D printing [63] and by the soft lithography process [64].

2.3 Green synthesis methods

The merge between nanotechnology and biology has led to the rise of a new and highly advanced field of nanomaterial synthesis using living microorganisms of both prokaryotic and eukaryotic origins, such as algae, bacteria, fungi, yeasts, viruses, and plants [65]. Within this framework, the synthesis of nanoparticles via green technologies utilizing microorganisms and plant extracts is continuously emerging as a safe, cost-efficient, renewable, and environmentally friendly alternative [65, 66, 67, 68] which does not implicate complex protocols [69] or the use of intermediary base groups [70]. Additionally, green synthesis methods lead to the formation of nanoparticles with higher stability as they do not involve the use of chemicals that increase particle reactivity, enhanced biocompatibility, non-toxicity, and antimicrobial and anticancer properties [66, 67, 68, 69]. Such methods are possible due to the resistance mechanisms developed by microorganisms and plants to endure the highly toxic environments generated by high metal concentrations. Specifically, the intrinsic chemical processes of these living entities can remodel inorganic metal ions into nanoparticles to reduce or eliminate the toxic effects. There are two main processes involved in the biogenic synthesis of nanoparticles, namely, through bioreduction, i.e., the reduction of metal ions by intrinsic biological processes, and biosorption, involving the assimilation of metal ions within the cell wall and the consequent formation of stable nanoparticulate structures through the assembly with the present macromolecules [65].

Generally, plant-based synthesis of nanoparticles is more advantageous in terms of higher kinetics, increased reduction and stabilization yield, and easier large-scale production [66, 68, 70]. The plant-mediated formation of nanoparticles can occur intracellularly or inside the plant, through the presence of specific biomolecules (e.g., aldehydes, ketones, flavones, phenols, amino acids, proteins, polysaccharides, tannins, terpenoids, saponins, vitamins), extracellularly, using plant extracts, or through individual phytochemicals. The mechanism involves the linkage between the atmospheric or phytochemical-generated oxygen that reduces the metal ions, followed by the electrostatic interactions between the newly formed metal oxides that will lead to the formation of the nanoparticles. The nature of the phytochemicals is responsible for their size, shape, stability, and reactivity variations [67, 68, 71]. Based on their produced phytochemicals, various plant parts have been investigated, including root, leaf, flower, petal, fruit, stem, peel, or seed [70].

Although green synthesis methods have been mostly applied for obtaining silver, gold, and copper nanoparticles, the synthesis of iron oxide nanoparticles through the use of plants or microorganisms has become an intensively studied field owing to the biocompatible, non-toxic, and stable nature of the final products [72]. Thus, there are many protocols available in the literature for the green synthesis of iron oxide nanoparticles, which generally follow a similar methodology. Briefly, the procedure begins with the starting material preparation and extraction, by collecting, washing, drying, weighing, grinding into a fine powder, boiling in water or methanol/ethanol under continuous stirring, centrifugation, and filtration. Subsequently, the extract is mixed with the precursor salt solutions, such as FeSO4·7H2O, FeCl3·6H2O, (FeNO3)3·9H2O, FeSO4, FeCl3, FeCl2·4H2O, FeCl2, or FeSO4·5H2O, of varying molarities. Finally, the mixture is heated and vigorously stirred until the color of the solution changes and intensifies according to the type of iron salts utilized. The obtained iron oxide nanoparticle pellets are further washed and dried [73].

The available literature studies reported the synthesis of iron oxide nanoparticles using Bauhinia tomentosa [74], pomegranate seeds [75], Hibiscus rosa-sinensis [76], Mimosa pudica root [77], Carica papaya leaf extract [78], Cymbopogon citratus [79], Ficus carica leaf extract [80], and Platanus orientalis leaf extract [81].

Advertisement

3. Advanced iron oxide nanoparticles characterization techniques

As previously emphasized, the physico-chemical properties of iron oxide nanoparticles often dictate their applications [82]. Since the characterization of nanoparticles is significantly challenging due to the increased interdisciplinarity of the field, it is fundamentally important to characterize nanoparticles to the maximum extent to ensure a more rapid implementation in commercial applications [83]. Generally, the physicochemical properties of iron oxide nanoparticles are evaluated through a variety of different techniques, depending on the parameter that must be determined [35, 73, 82]. Table 1 depicts the most important characteristics of iron oxide nanoparticles and the suitable characterization techniques for determining them.

Nanoparticle propertyCharacterization techniques
SizeTEM, XRD, DLS, NTA, HRTEM, SAXS, SEM, AFM
Size distributionDLS, NTA, SAXS
ShapeTEM, HRTEM, SEM, AFM, STEM
Crystal structureXRD, HRTEM, SAED, STEM
Elemental/chemical compositionXRD, SEM-EDX, ICP-MS, XPS, EELS
Surface area/specific surface areaBET analysis, NMR
Surface chargeZeta potential
Magnetic propertiesVSM, SQUID, Mössbauer spectroscopy, MFM

Table 1.

The characteristics of iron oxide nanoparticles and the associated characterization techniques. Adapted from an open-access source [35, 73, 83].

TEM—transmission electron microscopy, XRD—X-ray diffraction, DLS—dynamic light scattering, NTA—nanoparticle tracking analysis, HRTEM—high-resolution TEM, SAXS—small-angle X-ray scattering, SEM—scanning electron microscopy, AFM—atomic force microscopy, STEM—scanning transmission electron microscope, SAED—selected area electron diffraction, EDX—energy-dispersive X-ray spectroscopy, ICP-MS—inductively coupled plasma mass spectrometry, XPS—X-ray photoelectron spectroscopy, EELS—electron energy loss spectroscopy, BET—Brunauer–Emmett–Teller, NMR—nuclear magnetic resonance, VSM—vibrating sample magnetometry, SQUID—superconducting quantum interference device, MFM—magnetic force microscopy.

The most important parameter to be evaluated is the size and consequently the size distribution of the nanoparticles, as it can affect other properties and determine the behavior of the final product within the envisaged application [35, 83]. Although size measurements within the macroscale might appear trivial, size determinations within the nanoregime might lead to different interpretations depending on the characterization technique employed. When referring to nanoparticles, size can be correlated to the atomic structure-defined physical dimension, the diffusion/sedimentation-dependent effective size of the nanoparticle within a matrix or solvent, or the effective size weighted by the mass/electron distribution [84, 85]. Furthermore, size distribution represents an estimation of the quality of the synthesis process, as the general aim is to obtain close to monodisperse nanoparticles [82, 83, 84].

The shape also plays a fundamental role upon the behavior of iron oxide nanoparticles, as it can further lead to toxic effects due to cell harming. Therefore, the employed synthesis routes must allow for the control of nanoparticle shape as a crucial parameter [86, 87]. Commonly, electron microscopy techniques are utilized for the precise evaluation of the morphology and consequently the shape of the nanoparticles [83, 88].

Moreover, crystal structure and chemical composition also represent essential characterization steps in the process of iron oxide nanoparticle development [83]. Although X-ray diffraction represents the most common technique for crystal structure, crystallinity, and phases evaluation [89], studies have shown that in the case of nanoparticles with sizes below 5 nm, the diffractogram patterns are influenced [90]. Thus, other, more reliable methods should be developed. Selected area electron diffraction represents an alternative that better depicts the crystal structure of nanoparticles [84]. Chemical and elemental composition determination provides an estimation of the purity of the nanoparticles. Additionally, the chemical composition is a key parameter that can influence the electrochemical activity of the nanoparticles [91]. Moreover, another interesting characterization possibility involves the precise distinction between iron(II) and iron(III) to differentiate the iron oxide phases present within the nanoparticles, which could be possible through the electron energy loss spectroscopy method [92].

Although it might result in high agglomeration degrees, high surface areas of iron oxide nanoparticles are essential for ensuring the desired application [83, 87]. For example, in waste or pollutant removal applications, iron oxide nanoparticles must possess high surface areas to increase capture and immobilization efficiency [93]. Surface area is determined through straightforward gas sorption techniques, such as the BET analysis [84].

The surface charge can be correlated with the colloidal stability and interactions of the nanoparticles. Specifically, the interactions of iron oxide nanoparticles within the biological fluids will determine the formation of the protein corona on their surface and, thus, the probability of cellular uptake [84]. Generally, the surface charge of nanoparticles is measured through a zeta potentiometer by applying a voltage to the samples. The results are given in terms of zeta potential ζ, which refers to the difference in the electric potential between the particle surrounding stationary charge layers and the potential of the solution [94, 95, 96, 97]. Zeta potential values higher than +15 mV and lower than −15 mV are usually attributed to colloidally stable suspensions, as they generate electrostatic repulsions that are strong enough to counteract aggregation of the nanoparticles [82, 84, 85]. However, there are several parameters that could influence the zeta potential, such as the pH and ionic strength of the solvent or the presence of charged/uncharged molecules that can be adsorbed onto the surface of the nanoparticles [84].

Considering the extensive studies performed toward hyperthermia applications for controlled drug delivery and cancer therapy, an essential characteristic of iron oxide nanoparticles is their magnetic behavior. The magnetic properties of iron oxide nanoparticles directly depend upon the synthesis route and the size and shape of the obtained nanostructures [35]. Similar to other properties, the magnetic behavior of nanostructured materials is significantly different than those of the bulk materials, since the size decrease leads to changes from the multidomain to the single domain and, finally, to the superparamagnetic state [83]. Specifically, nanoparticles with superparamagnetic properties are characterized by negligible remanent magnetization and coercive field. Thus, when the external magnetic field is removed, the nanoparticles exhibit no magnetism. By contrast, ferro- and ferrimagnetic nanoparticles feature a magnetic hysteresis, associated with a remanent magnetization, thus requiring a coercive field for reverting the magnetization to zero [35, 98]. Furthermore, the magnetic behavior can also be influenced by the agglomeration and aggregation processes, which further favor dipole-dipole or exchange interactions [99]. There are several methods that can be utilized for the analysis of iron oxide nanoparticle magnetism, each associated with specific sensitivities [35].

Advertisement

4. Conclusions

Iron oxide nanoparticles have been intensively studied for a variety of applications within numerous fields, ranging from medicine and pharmaceutics to microelectronics and analytical chemistry. Since their utilization is continuously rising, the need for improving the currently available synthesis methods is fundamental. In this context, novel preparation routes must be explored to develop uniform and standardized iron oxide nanoparticles. Among the recently implemented strategies, microwave-assisted, microfluidics, and green synthesis methods have demonstrated an undoubted potential toward reaching this goal. Specifically, nanoparticles obtained through these methods were characterized by superior properties as compared to the co-precipitation counterparts. Furthermore, the advancements within the characterization techniques could further lead to new insights and potential improvements within this area. In this context, the most important techniques often include size, shape, structure, crystallinity, and magnetic behavior determinations. Therefore, the intensive research work investigating the synthesis of iron oxide nanoparticles must further continue.

Advertisement

Acknowledgments

We acknowledge the support of the research grant from the Romanian National Authority for Scientific Research and Innovation, UEFISCDI, project number TE 103, code: PN-III-P1-1.1-TE-2019-1450, entitled multifunctional lab-on-a-chip microfluidic platform for the fabrication of nanoparticles.

Advertisement

Conflict of interest

The authors declare no conflict of interest.

Advertisement

Notes/thanks/other declarations

We thank the esteemed group of researchers that have created the National Research Center for Micro and Nanomaterials from the University Politehnica of Bucharest and have considerably contributed to the development of numerous research studies.

References

  1. 1. Gahlot P, Aboudi K, Ahmed B, Tawfik A, Khan AA, Khursheed A, et al. Chapter 9—Direct interspecies electron transfer (DIET) via conductive materials in anaerobic digestion of organic wastes. In: Tyagi V, Aboudi K, editors. Clean Energy and Resources Recovery. Amsterdam, The Netherlands: Elsevier; 2021. pp. 227-252
  2. 2. Ahmadi M. 16—Iron oxide nanoparticles for delivery purposes. In: Mozafari M, editor. Nanoengineered Biomaterials for Advanced Drug Delivery. Amsterdam, The Netherlands: Elsevier; 2020. p. 373-393
  3. 3. Mishra M, Chun D-M. α-Fe2O3 as a photocatalytic material: A review. Applied Catalysis A: General. 2015;498:126-141. DOI: 10.1016/j.apcata.2015.03.023
  4. 4. Schwertmann U, Taylor RM. Iron oxides. Minerals in soil environments. 1989;1:379-438
  5. 5. Claudio C, Iorio E, Liu Q, Jiang Z, Barrón V. Iron oxide nanoparticles in soils: Environmental and agronomic importance. Journal of Nanoscience and Nanotechnology. 2017;17(7):4449-4460
  6. 6. Von der Heyden B, Roychoudhury A, Myneni S. Iron-rich nanoparticles in natural aquatic environments. Minerals. 2019;9(5):287
  7. 7. Ezealigo US, Ezealigo BN, Aisida SO, Ezema FI. Iron oxide nanoparticles in biological systems: Antibacterial and toxicology perspective. JCIS Open. 2021;4:100027. DOI: 10.1016/j.jciso.2021.100027
  8. 8. Moura RP, Sousa F, Almeida A, Pinto S, Sarmento B. 13—Theranostic biomaterials for regulation of the blood–brain barrier. In: Cui W, Zhao X, editors. Theranostic Bionanomaterials. Amsterdam, The Netherlands: Elsevier; 2019. p. 303-319
  9. 9. de Jesus PdC C, Pellosi DS, Tedesco AC. Chapter 12—Magnetic nanoparticles: Applications in biomedical processes as synergic drug-delivery systems. In: Holban A-M, Grumezescu AM, editors. Materials for Biomedical Engineering. Amsterdam, The Netherlands: Elsevier; 2019. pp. 371-396
  10. 10. Baumgartner J, Faivre D. Iron solubility, colloids and their impact on iron (oxyhydr)oxide formation from solution. Earth-Science Reviews. 2015;150:520-530
  11. 11. Hiemstra T. Formation, stability, and solubility of metal oxide nanoparticles: Surface entropy, enthalpy, and free energy of ferrihydrite. Geochimica et Cosmochimica Acta. 2015;158:179-198
  12. 12. Weatherill JS, Morris K, Bots P, Stawski TM, Janssen A, Abrahamsen L, et al. Ferrihydrite formation: The role of Fe13 Keggin clusters. Environmental Science and Technology. 2016;50(17):9333-9342
  13. 13. Chernyshova IV, Ponnurangam S, Somasundaran P. Linking interfacial chemistry of CO2 to surface structures of hydrated metal oxide nanoparticles: Hematite. Physical Chemistry Chemical Physics. 2013;15(18):6953-6964
  14. 14. Singla A, Marwaha A, Marwaha S, Chavali M. Chapter 2—Green nanomaterials: Pioneering approach toward hyperthermia treatment. In: Kharisov B, Kharissova O, editors. Handbook of Greener Synthesis of Nanomaterials and Compounds. Amsterdam, The Netherlands: Elsevier; 2021. pp. 487-502
  15. 15. Jean-Pierre J, Elisabeth T, Corinne C. Iron oxides: From molecular clusters to solid. A nice example of chemical versatility. Comptes Rendus Geoscience. 2006;338:488-497
  16. 16. Miyazaki T. 4—Organic modification of magnetite nanoparticles for biomedical applications. In: Osaka A, Narayan R, editors. Bioceramics. Amsterdam, The Netherlands: Elsevier; 2021. pp. 77-82
  17. 17. Daoush WM. Co-precipitation and magnetic properties of magnetite nanoparticles for potential biomedical applications. Journal of Nanomedicine Research. 2017;5(3):00118
  18. 18. Ganapathe LS, Mohamed MA, Mohamad Yunus R, Berhanuddin DD. Magnetite (Fe3O4) nanoparticles in biomedical application: From synthesis to surface functionalisation. Magnetochemistry. 2020;6(4):68. DOI: 10.3390/magnetochemistry6040068
  19. 19. Ortega G, Reguera E. Chapter 13—Biomedical applications of magnetite nanoparticles. In: Holban A-M, Grumezescu AM, editors. Materials for Biomedical Engineering. Amsterdam, The Netherlands: Elsevier; 2019. pp. 397-434
  20. 20. Sajid M, Płotka-Wasylka J. Nanoparticles: Synthesis, characteristics, and applications in analytical and other sciences. Microchemical Journal. 2020;154:104623. DOI: 10.1016/j.microc.2020.104623
  21. 21. Goswami L, Kim K-H, Deep A, Das P, Bhattacharya SS, Kumar S, et al. Engineered nano particles: Nature, behavior, and effect on the environment. Journal of Environmental Management. 2017;196:297-315
  22. 22. Tanaka S, Kaneti YV, Septiani NLW, Dou SX, Bando Y, Hossain MSA, et al. A review on iron oxide-based nanoarchitectures for biomedical, energy storage, and environmental applications. Small Methods. 2019;3(5):1800512
  23. 23. Gao L, Zhuang J, Nie L, Zhang J, Zhang Y, Gu N, et al. Intrinsic peroxidase-like activity of ferromagnetic nanoparticles. Nature Nanotechnology. 2007;2(9):577-583. DOI: 10.1038/nnano.2007.260
  24. 24. Huang X-L, Zhang J-Z. Hydrolysis of glucose-6-phosphate in aged, acid-forced hydrolysed nanomolar inorganic iron solutions—An inorganic biocatalyst? RSC Advances. 2012;2(1):199-208
  25. 25. Huang X-L. Hydrolysis of phosphate esters catalyzed by inorganic iron oxide nanoparticles acting as biocatalysts. Astrobiology. 2018;18(3):294-310
  26. 26. Wei H, Wang E. Fe3O4 magnetic nanoparticles as peroxidase mimetics and their applications in H2O2 and glucose detection. Analytical Chemistry. 2008;80(6):2250-2254
  27. 27. Lin Y, Ren J, Qu X. Catalytically active nanomaterials: A promising candidate for artificial enzymes. Accounts of Chemical Research. 2014;47(4):1097-1105
  28. 28. Zhou Y, Liu B, Yang R, Liu J. Filling in the gaps between nanozymes and enzymes: Challenges and opportunities. Bioconjugate Chemistry. 2017;28(12):2903-2909
  29. 29. Huang X-L. Iron oxide nanoparticles: An inorganic phosphatase. In: Nanocatalysts. London, United Kingdom: IntechOpen; 2019
  30. 30. Akbarzadeh A, Samiei M, Davaran S. Magnetic nanoparticles: Preparation, physical properties, and applications in biomedicine. Nanoscale Research Letters. 2012;7(1):144. DOI: 10.1186/1556-276X-7-144
  31. 31. Gatoo M, Naseem S, Arfat M, Dar A, Qasim K, Zubair S. Physicochemical properties of nanomaterials: Implication in associated toxic manifestations. BioMed Research International. 2014;2014:498420. DOI: 10.1155/2014/498420
  32. 32. Hui BH, Salimi MN. Production of iron oxide nanoparticles by co-precipitation method with optimization studies of processing temperature, pH and stirring rate. IOP Conference Series: Materials Science and Engineering. 2020;743:012036. DOI: 10.1088/1757-899x/743/1/012036
  33. 33. Zhang J, Tang H, Liu Z, Chen B. Effects of major parameters of nanoparticles on their physical and chemical properties and recent application of nanodrug delivery system in targeted chemotherapy. International Journal of Nanomedicine. 2017;12:8483
  34. 34. LaGrow AP, Besenhard MO, Hodzic A, Sergides A, Bogart LK, Gavriilidis A, et al. Unravelling the growth mechanism of the co-precipitation of iron oxide nanoparticles with the aid of synchrotron X-Ray diffraction in solution. Nanoscale. 2019;11(14):6620-6628. DOI: 10.1039/C9NR00531E
  35. 35. Ali A, Shah T, Ullah R, Zhou P, Guo M, Ovais M, et al. Review on recent progress in magnetic nanoparticles: Synthesis, characterization, and diverse applications. Frontiers in Chemistry. 2021;9(548):629054. DOI: 10.3389/fchem.2021.629054
  36. 36. Schwaminger SP, Syhr C, Berensmeier S. Controlled synthesis of magnetic iron oxide nanoparticles: Magnetite or maghemite? Crystals. 2020;10(3):214. DOI: 10.3390/cryst10030214
  37. 37. Guo H, Barnard AS. Naturally occurring iron oxide nanoparticles: Morphology, surface chemistry and environmental stability. Journal of Materials Chemistry A. 2013;1(1):27-42
  38. 38. Niculescu A-G, Chircov C, Grumezescu AM. Magnetite nanoparticles: Synthesis methods—A comparative review. Methods. 2021. (In Press). DOI: 10.1016/j.ymeth.2021.04.018
  39. 39. Singh JP, Kumar M, Sharma A, Pandey G, Chae KH, Lee S. Bottom-up and top-down approaches for MgO. In: Sonochemical Reactions. London, United Kingdom: IntechOpen; 2020
  40. 40. Priyadarshana G, Kottegoda N, Senaratne A, de Alwis A, Karunaratne V. Synthesis of magnetite nanoparticles by top-down approach from a high purity ore. Journal of Nanomaterials. 2015;2015:317312. DOI: 10.1155/2015/317312
  41. 41. Aryal S, Park H, Leary JF, Key J. Top-down fabrication-based nano/microparticles for molecular imaging and drug delivery. International Journal of Nanomedicine. 2019;14:6631
  42. 42. Baig N, Kammakakam I, Falath W. Nanomaterials: A review of synthesis methods, properties, recent progress, and challenges. Materials Advances. 2021;2(6):1821-1871
  43. 43. Mihai AD, Chircov C, Grumezescu AM, Holban AM. Magnetite nanoparticles and essential oils systems for advanced antibacterial therapies. International Journal of Molecular Sciences. 2020;21(19):7355. DOI: 10.3390/ijms21197355
  44. 44. Rashid H, Mansoor MA, Haider B, Nasir R, Abd Hamid SB, Abdulrahman A. Synthesis and characterization of magnetite nano particles with high selectivity using in-situ precipitation method. Separation Science and Technology. 2020;55(6):1207-1215. DOI: 10.1080/01496395.2019.1585876
  45. 45. Ansari SAMK, Ficiarà E, Ruffinatti FA, Stura I, Argenziano M, Abollino O, et al. Magnetic iron oxide nanoparticles: Synthesis, characterization and functionalization for biomedical applications in the central nervous system. Materials. 2019;12(3):465
  46. 46. Wallyn J, Anton N, Vandamme TF. Synthesis, principles, and properties of magnetite nanoparticles for in vivo imaging applications-a review. Pharmaceutics. 2019;11(11):601. DOI: 10.3390/pharmaceutics11110601
  47. 47. Liu S, Yu B, Wang S, Shen Y, Cong H. Preparation, surface functionalization and application of Fe3O4 magnetic nanoparticles. Advances in Colloid and Interface Science. 2020;281:102165. DOI: 10.1016/j.cis.2020.102165
  48. 48. Wu W, Jiang CZ, Roy VA. Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications. Nanoscale. 2016;8(47):19421-19474. DOI: 10.1039/c6nr07542h
  49. 49. Dahiya MS, Tomer VK, Duhan S. 31—Metal–ferrite nanocomposites for targeted drug delivery. In: Inamuddin, Asiri AM, Mohammad A, editors. Applications of Nanocomposite Materials in Drug Delivery. Cambridge, United Kingdom: Woodhead Publishing; 2018. pp. 737-760
  50. 50. Morsali A, Hashemi L. Chapter 2—Nanoscale coordination polymers: Preparation, function and application. In: Ruiz-Molina D, van Eldik R, editors. Advances in Inorganic Chemistry. 76: London, United Kingdom: Academic Press; 2020. p. 33-72
  51. 51. Gupta D, Jamwal D, Rana D, Katoch A. 26—Microwave synthesized nanocomposites for enhancing oral bioavailability of drugs. In: Inamuddin, Asiri AM, Mohammad A, editors. Applications of Nanocomposite Materials in Drug Delivery. Cambridge, United Kingdom: Woodhead Publishing; 2018. pp. 619-632
  52. 52. Bandyopadhyay D, Banik BK. Chapter 3—Microwave-assisted synthesis of medicinally privileged heterocycles. In: Brahmachari G, editor. Green Synthetic Approaches for Biologically Relevant Heterocycles. 2nd ed. Amsterdam, The Netherlands: Elsevier; 2021. pp. 49-110
  53. 53. Aivazoglou E, Metaxa E, Hristoforou E. Microwave-assisted synthesis of iron oxide nanoparticles in biocompatible organic environment. AIP Advances. 2018;8(4):048201. DOI: 10.1063/1.4994057
  54. 54. Kostyukhin EM, Kustov LM. Microwave-assisted synthesis of magnetite nanoparticles possessing superior magnetic properties. Mendeleev Communications. 2018;28(5):559-561. DOI: 10.1016/j.mencom.2018.09.038
  55. 55. Chircov C, Matei M-F, Neacșu IA, Vasile BS, Oprea O-C, Croitoru A-M, et al. Iron oxide–silica core–shell nanoparticles functionalized with essential oils for antimicrobial therapies. Antibiotics. 2021;10(9):1138
  56. 56. Brollo MEF, Veintemillas-Verdaguer S, Salván CM, MdP M. Key parameters on the microwave assisted synthesis of magnetic nanoparticles for MRI contrast agents. Contrast Media & Molecular Imaging. 2017;2017:8902424. DOI: 10.1155/2017/8902424
  57. 57. Chircov C, Bîrcă AC, Grumezescu AM, Vasile BS, Oprea O, Nicoară AI, et al. Synthesis of magnetite nanoparticles through a lab-on-chip device. Materials. 2021;14(19):5906. DOI: 10.3390/ma14195906
  58. 58. Chircov C, Bîrcă AC, Grumezescu AM, Andronescu E. Biosensors-on-chip: An up-to-date review. Molecules. 2020;25(24):6013. DOI: 10.3390/molecules25246013
  59. 59. Niculescu A-G, Chircov C, Bîrcă AC, Grumezescu AM. Nanomaterials synthesis through microfluidic methods: An updated overview. Nanomaterials. 2021;11(4):864. DOI: 10.3390/nano11040864
  60. 60. Abedini-Nassab R, Pouryosef Miandoab M, Şaşmaz M. Microfluidic synthesis, control, and sensing of magnetic nanoparticles: A review. Micromachines (Basel). 2021;12(7):768. DOI: 10.3390/mi12070768
  61. 61. Thu VT, Mai AN, Le The T, Van Trung H, Thu PT, Tien BQ, et al. Fabrication of PDMS-based microfluidic devices: Application for synthesis of magnetic nanoparticles. Journal of Electronic Materials. 2016;45(5):2576-2581. DOI: 10.1007/s11664-016-4424-6
  62. 62. Bemetz J, Wegemann A, Saatchi K, Haase A, Häfeli UO, Niessner R, et al. Microfluidic-based synthesis of magnetic nanoparticles coupled with miniaturized NMR for online relaxation studies. Analytical Chemistry. 2018;90(16):9975-9982. DOI: 10.1021/acs.analchem.8b02374
  63. 63. Aşık MD, Kaplan M, Çetin B, Sağlam N. Synthesis of iron oxide core chitosan nanoparticles in a 3D printed microfluidic device. Journal of Nanoparticle Research. 2021;23(3):62. DOI: 10.1007/s11051-021-05171-y
  64. 64. Siavashy S, Soltani M, Ghorbani-Bidkorbeh F, Fallah N, Farnam G, Mortazavi SA, et al. Microfluidic platform for synthesis and optimization of chitosan-coated magnetic nanoparticles in cisplatin delivery. Carbohydrate Polymers. 2021;265:118027. DOI: 10.1016/j.carbpol.2021.118027
  65. 65. Zhang D, Ma X-l, Gu Y, Huang H, Zhang G-w. Green synthesis of metallic nanoparticles and their potential applications to treat cancer. Frontiers in Chemistry. 2020;8:799. DOI: 10.3389/fchem.2020.00799
  66. 66. Ahmad S, Munir S, Zeb N, Ullah A, Khan B, Ali J, et al. Green nanotechnology: A review on green synthesis of silver nanoparticles—An ecofriendly approach. International Journal of Nanomedicine. 2019;14:5087
  67. 67. Gour A, Jain NK. Advances in green synthesis of nanoparticles. Artificial Cells, Nanomedicine, and Biotechnology. 2019;47(1):844-851. DOI: 10.1080/21691401.2019.1577878
  68. 68. Dikshit PK, Kumar J, Das AK, Sadhu S, Sharma S, Singh S, et al. Green synthesis of metallic nanoparticles: Applications and limitations. Catalysts. 2021;11(8):902
  69. 69. Naikoo GA, Mustaqeem M, Hassan IU, Awan T, Arshad F, Salim H, et al. Bioinspired and green synthesis of nanoparticles from plant extracts with antiviral and antimicrobial properties: A critical review. Journal of Saudi Chemical Society. 2021;25(9):101304. DOI: 10.1016/j.jscs.2021.101304
  70. 70. Jadoun S, Arif R, Jangid NK, Meena RK. Green synthesis of nanoparticles using plant extracts: A review. Environmental Chemistry Letters. 2021;19(1):355-374. DOI: 10.1007/s10311-020-01074-x
  71. 71. Shafey AME. Green synthesis of metal and metal oxide nanoparticles from plant leaf extracts and their applications: A review. Green Processing and Synthesis. 2020;9(1):304-339. DOI: 10.1515/gps-2020-0031
  72. 72. Yadwade R, Kirtiwar S, Ankamwar B. A review on green synthesis and applications of iron oxide nanoparticles. Journal of Nanoscience and Nanotechnology. 2021;21(12):5812-5834
  73. 73. Priya N, Kaur K, Sidhu AK. Green synthesis: An eco-friendly route for the synthesis of iron oxide nanoparticles. Frontiers in Nanotechnology. 2021;3(47):655062. DOI: 10.3389/fnano.2021.655062
  74. 74. Lakshminarayanan S, Shereen MF, Niraimathi KL, Brindha P, Arumugam A. One-pot green synthesis of iron oxide nanoparticles from Bauhinia tomentosa: Characterization and application towards synthesis of 1,3 diolein. Scientific Reports. 2021;11(1):8643. DOI: 10.1038/s41598-021-87960-y
  75. 75. Bibi I, Nazar N, Ata S, Sultan M, Ali A, Abbas A, et al. Green synthesis of iron oxide nanoparticles using pomegranate seeds extract and photocatalytic activity evaluation for the degradation of textile dye. Journal of Materials Research and Technology. 2019;8(6):6115-6124. DOI: 10.1016/j.jmrt.2019.10.006
  76. 76. Razack SA, Suresh A, Sriram S, Ramakrishnan G, Sadanandham S, Veerasamy M, et al. Green synthesis of iron oxide nanoparticles using Hibiscus rosa-sinensis for fortifying wheat biscuits. SN Applied Sciences. 2020;2(5):898. DOI: 10.1007/s42452-020-2477-x
  77. 77. Niraimathee VA, Subha V, Ramaswami Sachidanandan ER, Renganathan S. Green synthesis of iron oxide nanoparticles from Mimosa pudica root extract. International Journal of Environment and Sustainable Development. 2016;15:227. DOI: 10.1504/IJESD.2016.077370
  78. 78. Paul S, Aka T, Ashaduzzaman M, Rahaman MM, Otun S. Green synthesis of iron oxide nanoparticle using Carica papaya leaf extract: Application for photocatalytic degradation of remazol yellow RR dye and antibacterial activity. Heliyon. 2020;6:e04603. DOI: 10.1016/j.heliyon.2020.e04603
  79. 79. Patiño-Ruiz DA, Meramo-Hurtado SI, González-Delgado ÁD, Herrera A. Environmental sustainability evaluation of iron oxide nanoparticles synthesized via green synthesis and the coprecipitation method: A comparative life cycle assessment study. ACS Omega. 2021;6(19):12410-12423. DOI: 10.1021/acsomega.0c05246
  80. 80. Üstün E, Önbaş SC, Çelik SK, Ayvaz MÇ, Şahin N. Green synthesis of iron oxide nanoparticles by using Ficus carica leaf extract and its antioxidant activity. Biointerface Research in Applied Chemistry. 2022;2021(12):2108-2116
  81. 81. Devi HS, Boda MA, Shah MA, Parveen S, Wani AH. Green synthesis of iron oxide nanoparticles using Platanus orientalis leaf extract for antifungal activity. Green Processing and Synthesis. 2019;8(1):38-45. DOI: 10.1515/gps-2017-0145
  82. 82. Anu Mary Ealia S, Saravanakumar MP. A review on the classification, characterisation, synthesis of nanoparticles and their application. IOP Conference Series: Materials Science and Engineering. 2017;263:032019. DOI: 10.1088/1757-899x/263/3/032019
  83. 83. Mourdikoudis S, Pallares RM, Thanh NTK. Characterization techniques for nanoparticles: Comparison and complementarity upon studying nanoparticle properties. Nanoscale. 2018;10(27):12871-12934. DOI: 10.1039/C8NR02278J
  84. 84. Modena MM, Rühle B, Burg TP, Wuttke S. Nanoparticle characterization: What to measure? Advanced Materials. 2019;31(32):1901556. DOI: 10.1002/adma.201901556
  85. 85. Bélteky P, Rónavári A, Zakupszky D, Boka E, Igaz N, Szerencsés B, et al. Are smaller nanoparticles always better? understanding the biological effect of size-dependent silver nanoparticle aggregation under biorelevant conditions. International Journal of Nanomedicine. 2021;16:3021
  86. 86. Arno MC, Inam M, Weems AC, Li Z, Binch ALA, Platt CI, et al. Exploiting the role of nanoparticle shape in enhancing hydrogel adhesive and mechanical properties. Nature Communications. 2020;11(1):1420. DOI: 10.1038/s41467-020-15206-y
  87. 87. Gomathi T, Rajeshwari K, Kanchana V, Sudha PN, Parthasarathy K. Impact of nanoparticle shape, size, and properties of the sustainable nanocomposites. In: Inamuddin, Thomas S, Kumar Mishra R, Asiri AM, editors. Sustainable Polymer Composites and Nanocomposites. Cham: Springer International Publishing; 2019. pp. 313-336
  88. 88. Boselli L, Lopez H, Zhang W, Cai Q, Giannone VA, Li J, et al. Classification and biological identity of complex nano shapes. Communications Materials. 2020;1(1):35. DOI: 10.1038/s43246-020-0033-2
  89. 89. Khan I, Saeed K, Khan I. Nanoparticles: Properties, applications and toxicities. Arabian Journal of Chemistry. 2019;12(7):908-931. DOI: 10.1016/j.arabjc.2017.05.011
  90. 90. Vorontsov AV, Tsybulya SV. Influence of nanoparticles size on XRD patterns for small monodisperse nanoparticles of Cu0 and TiO2 anatase. Industrial and Engineering Chemistry Research. 2018;57(7):2526-2536. DOI: 10.1021/acs.iecr.7b04480
  91. 91. Mukundan V, Shan S, Zhong C-J, Malis O. Effect of chemical composition on the nanoscale ordering transformations of physical mixtures of Pd and Cu nanoparticles. Journal of Nanomaterials. 2018;2018:9087320. DOI: 10.1155/2018/9087320
  92. 92. Cavé L, Al T, Loomer D, Cogswell S, Weaver L. A STEM/EELS method for mapping iron valence ratios in oxide minerals. Micron. 2006;37(4):301-309. DOI: 10.1016/j.micron.2005.10.006
  93. 93. Koopmans GF, Hiemstra T, Vaseur C, Chardon WJ, Voegelin A, Groenenberg JE. Use of iron oxide nanoparticles for immobilizing phosphorus in-situ: Increase in soil reactive surface area and effect on soluble phosphorus. Science of the Total Environment. 2020;711:135220. DOI: 10.1016/j.scitotenv.2019.135220
  94. 94. Ismail AF, Khulbe KC, Matsuura T. Chapter 3—RO membrane characterization. In: Ismail AF, Khulbe KC, Matsuura T, editors. Reverse Osmosis. Amsterdam, The Netherlands: Elsevier; 2019. pp. 57-90
  95. 95. Kumar CV, Pattammattel A. Chapter 8—Graphene composites with proteins and biologics. In: Kumar CV, Pattammattel A, editors. Introduction to Graphene. Amsterdam, The Netherlands: Elsevier; 2017. pp. 155-186
  96. 96. Yamashita Y, Sakamoto K. Chapter 38—Structural analysis of formulations. In: Sakamoto K, Lochhead RY, Maibach HI, Yamashita Y, editors. Cosmetic Science and Technology. Amsterdam: Elsevier; 2017. pp. 635-655
  97. 97. Nasrollahzadeh M, Shafiei N, Soleimani F, Nezafat Z, Soheili Bidgoli NS. Chapter 10—Physicochemical characterization of biopolymer-based metal nanoparticles. In: Nasrollahzadeh M, editor. Biopolymer-Based Metal Nanoparticle Chemistry for Sustainable Applications. Amsterdam, The Netherlands: Elsevier; 2021. pp. 317-478
  98. 98. Maldonado-Camargo L, Unni M, Rinaldi C. Magnetic characterization of iron oxide nanoparticles for biomedical applications. Methods in Molecular Biology. 2017;1570:47-71. DOI: 10.1007/978-1-4939-6840-4_4
  99. 99. Gutiérrez L, de la Cueva L, Moros M, Mazarío E, de Bernardo S, de la Fuente JM, et al. Aggregation effects on the magnetic properties of iron oxide colloids. Nanotechnology. 2019;30(11):112001. DOI: 10.1088/1361-6528/aafbff

Written By

Cristina Chircov and Bogdan Stefan Vasile

Submitted: 20 November 2021 Reviewed: 26 November 2021 Published: 05 January 2022