A review on the structural characterization of nanomaterials for nano-QSAR models

• Salvador Moncho,
• Eva Serrano-Candelas,
• Jesús Vicente de Julián-Ortiz and
• Rafael Gozalbes

Beilstein J. Nanotechnol. 2024, 15, 854–866, doi:10.3762/bjnano.15.71

• coordination numbers [24]. Alternatively, Kotzabasaki et al. also codified the composition of iron oxide nanoparticles with a single categorical descriptor that encodes the crystal structure of the main component (in this case as maghemite or magnetite) [25]. Alternatively, some descriptors are focused on the

Laser synthesis of nanoparticles in organic solvents – products, reactions, and perspectives

• Theo Fromme,
• Sven Reichenberger,
• Katharine M. Tibbetts and
• Stephan Barcikowski

Beilstein J. Nanotechnol. 2024, 15, 638–663, doi:10.3762/bjnano.15.54

• gave rise to an amorphous iron core, while tetrahydrofuran and dimethyl sulfoxide formed magnetite/maghemite or metallic iron. Oxides were detected for acetonitrile and dimethylformamide, and ablation in ethanol resulted in iron carbides [100]. Iron carbide formation was also found for ablation in

Classification and application of metal-based nanoantioxidants in medicine and healthcare

• Nguyen Nhat Nam,
• Nguyen Khoi Song Tran,
• Tan Tai Nguyen,
• Nguyen Ngoc Trai,
• Nguyen Phuong Thuy,
• Hoang Dang Khoa Do,
• Nhu Hoa Thi Tran and
• Kieu The Loan Trinh

Beilstein J. Nanotechnol. 2024, 15, 396–415, doi:10.3762/bjnano.15.36

• -line ferrihydrite, 2-line ferrihydrite, goethite, akageneite, feroxyhyte, hematite, magnetite, maghemite, schwertmannite, and lepidocrocite were compared regarding CAT activity [34]. The highest CAT activity was shown by 2-line ferrihydrite, followed by 6-line ferrihydrite and feroxyhyte. Iron-based

Two-step single-reactor synthesis of oleic acid- or undecylenic acid-stabilized magnetic nanoparticles by thermal decomposition

• Mykhailo Nahorniak,
• Pamela Pasetto,
• Jean-Marc Greneche,
• Volodymyr Samaryk,
• Sandy Auguste,
• Anthony Rousseau,
• Nataliya Nosova and
• Serhii Varvarenko

Beilstein J. Nanotechnol. 2023, 14, 11–22, doi:10.3762/bjnano.14.2

• of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic Institut des Molécules et Matériaux du Mans (IMMM), UMR 6283 CNRS − Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans Cedex, France 10.3762/bjnano.14.2 Abstract Different iron oxides (i.e., magnetite, maghemite, goethite

• particle mass. The result is a significantly different resistance to oxidation of the nanoparticle inorganic cores. The core of the particles synthesized using oleic acid is composed of more than 90% of maghemite. When undecylenic acid is used for the synthesis, the core is composed of 75% of magnetite

• . Keywords: Fe(III) acetylacetonate; iron oxide nanoparticles; maghemite; magnetic nanoparticles; magnetite; thermal decomposition synthesis; Introduction Magnetic nanoparticles are increasingly being used in various fields thanks to the recent progress in their controlled synthesis and knowledge of their

Non-stoichiometric magnetite as catalyst for the photocatalytic degradation of phenol and 2,6-dibromo-4-methylphenol – a new approach in water treatment

• Joanna Kisała,
• Anna Tomaszewska and
• Przemysław Kolek

Beilstein J. Nanotechnol. 2022, 13, 1531–1540, doi:10.3762/bjnano.13.126

• as the parameter x = Fe2+/Fe3+) can range from 0.5 (stoichiometric magnetite Fe(III)tet[Fe(II),Fe(III)]octO4) to 0 (completely oxidized; maghemite, γ-Fe2O3) [24]. A magnetite with x values in the range of 0 < x < 0.5 is defined as non-stoichiometric or partially oxidized magnetite. Stoichiometric

• magnetite and maghemite are significantly different. Magnetite is a conductor (bandgap of 0.1 eV), while maghemite is a semiconductor (bandgap of approx. 2.0 eV) [12]. The unit cell parameter of magnetite is slightly larger (ca. 8.40 Å) than that of maghemite (ca. 8.34 Å). A combination of these properties

Theranostic potential of self-luminescent branched polyethyleneimine-coated superparamagnetic iron oxide nanoparticles

• Rouhollah Khodadust,
• Ozlem Unal and
• Havva Yagci Acar

Beilstein J. Nanotechnol. 2022, 13, 82–95, doi:10.3762/bjnano.13.6

• sensitivity the results obtained from TEM are usually more reliable [52]. The XRD pattern of SPION@bPEI synthesized in situ indicates a crystalline magnetite structure composed of both magnetite (Fe3O4) and maghemite (Fe2O3), including nanoparticles (Figure 1c). Considering only XRD patterns it would be

• difficult to distinguish the percentage of magnetite and maghemite in magnetic nanoparticles. However, electron paramagnetic resonance (EPR) spectroscopy analysis can be applied to overcome this problem. According to EPR spectroscopy results, SPION@bPEI nanoparticles synthesized in situ were composed of 23

• % magnetite and 77% of maghemite SPIONs [35]. Here, the cytotoxicity of SPION@bPEI, its potential for therapeutic gene delivery, and label-free optical imaging were investigated. For this purpose, PIC which is a synthetic dsRNA was electrostatically loaded into SPION@bPEI at different N/P ratios (1.4/1, 2.8/1

Antimicrobial metal-based nanoparticles: a review on their synthesis, types and antimicrobial action

• Matías Guerrero Correa,
• Fernanda B. Martínez,
• Cristian Patiño Vidal,
• Camilo Streitt,
• Juan Escrig and
• Carol Lopez de Dicastillo

Beilstein J. Nanotechnol. 2020, 11, 1450–1469, doi:10.3762/bjnano.11.129

• modification, intrinsic properties and the type of targeted microorganism [18]. A special category of metallic NPs is superparamagnetic iron-oxide nanoparticles (SPIONs) (e.g., magnetite (Fe3O4) and maghemite (γ-Fe2O3) NPs) whose antimicrobial activity increases upon the application of an external magnetic

• most known and studied SPIONs. Magnetite (Fe3O4) and maghemite (γ-Fe2O3) are two crystalline phases of iron oxide that present superparamagnetic properties at the nanoscale (<20 nm). This superparamagnetism is generated due to the reduced size of these nanoparticles which allow for a higher surface-to

Transient coating of γ-Fe₂O₃ nanoparticles with glutamate for its delivery to and removal from brain nerve terminals

• Konstantin Paliienko,
• Artem Pastukhov,
• Michal Babič,
• Daniel Horák,
• Olga Vasylchenko and
• Tatiana Borisova

Beilstein J. Nanotechnol. 2020, 11, 1381–1393, doi:10.3762/bjnano.11.122

• trauma, and epilepsy. Also, glutamate is a potential tumor growth factor. Using radiolabeled ʟ-[14C]glutamate and magnetic fields, we developed an approach for monitoring the biomolecular coating (biocoating) with glutamate of the surface of maghemite (γ-Fe2O3) nanoparticles. The nanoparticles decreased

• transient glutamate biocoating can be useful for multifunctional theranostics. Keywords: blood plasma; brain nerve terminals; glutamate biocoating; maghemite (γ-Fe2O3) nanoparticles; protein biocorona; Introduction Glutamate is a main fast excitatory neurotransmitter in the central nervous system. Normal

• Synthesis of superparamagnetic maghemite (γ-Fe2O3) nanoparticles γ-Fe2O3 nanoparticles were synthesized and characterized according to [21]. A 0.5 M solution of NH4OH (subaliquot amount needed for quantitative formation of Fe(OH)3) was added dropwise to a 0.5 M aqueous solution of FeCl3 under sonication

Magnetic-field-assisted synthesis of anisotropic iron oxide particles: Effect of pH

• Andrey V. Shibaev,
• Petr V. Shvets,
• Darya E. Kessel,
• Roman A. Kamyshinsky,
• Anton S. Orekhov,
• Sergey S. Abramchuk,
• Alexei R. Khokhlov and
• Olga E. Philippova

Beilstein J. Nanotechnol. 2020, 11, 1230–1241, doi:10.3762/bjnano.11.107

• reference sample (20–50 nm). It is well known that distinguishing between magnetite (Fe3O4) and maghemite (γ-Fe2O3) only using the diffraction technique is not straightforward. However, these samples can be easily distinguished by Raman scattering, since Fe3O4, γ-Fe2O3 and other iron oxides and hydroxides

Influence of the magnetic nanoparticle coating on the magnetic relaxation time

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2020, 11, 1207–1216, doi:10.3762/bjnano.11.105

• generating heat. This heat increases the tumour cell temperature which leads to cell death [1][2][3][4]. Iron-oxide magnetic nanoparticles, in particular magnetite (Fe3O4) and maghemite (γ-Fe2O3), have been intensely studied in the context of magnetic hyperthermia applications. These nanoparticles can be

Applications of superparamagnetic iron oxide nanoparticles in drug and therapeutic delivery, and biotechnological advancements

• Maria Suciu,
• Corina M. Ionescu,
• Alexandra Ciorita,
• Septimiu C. Tripon,
• Dragos Nica,
• Hani Al-Salami and
• Lucian Barbu-Tudoran

Beilstein J. Nanotechnol. 2020, 11, 1092–1109, doi:10.3762/bjnano.11.94

• of iron oxides in the form of magnetite (Fe3O4) or maghemite (Fe2O3) and are easy to produce through a few well-documented synthesis methods yielding different forms and structures (e.g., round, cubic, hexagonal, clusters, core–shell with gold, silica, polymers, or surfactants). A lot of research is

• trials [51]. A recent report suggests that submandibular gland cells suffer epigenetic mutations when treated with maghemite [52]. This fact becomes very important especially when developing SPION treatments for cancer. Unfortunately, to date scientists and physicians cannot provide definite protocols

• magnetite (Fe3O4), maghemite (γ-Fe2O3) or hematite (α-Fe2O3) [60]. There are various geometric forms of SPIONs, which depend on the synthesis. The most extensively studied form are spherical SPIONs, followed by cubic, hexagonal, rod-like, octagonal, nanoworm, and octopod (star-shaped) SPIONs [61][62]. Non

Key for crossing the BBB with nanoparticles: the rational design

• Sonia M. Lombardo,
• Marc Schneider,
• Akif E. Türeli and
• Nazende Günday Türeli

Beilstein J. Nanotechnol. 2020, 11, 866–883, doi:10.3762/bjnano.11.72

• ) are based on magnetite (Fe3O4) or maghemite (γ-Fe2O3) molecules encapsulated in polysaccharides, synthetic polymers or monomer coatings and have a size range from 1 to 100 nm [21][182]. SPIONs possess interesting magnetic properties and some formulations have already been approved as MRI contrast

Magnetic properties of biofunctionalized iron oxide nanoparticles as magnetic resonance imaging contrast agents

• Natalia E. Gervits,
• Andrey A. Gippius,
• Alexey V. Tkachev,
• Evgeniy I. Demikhov,
• Sergey S. Starchikov,
• Igor S. Lyubutin,
• Alexander L. Vasiliev,
• Vladimir P. Chekhonin,
• Maxim A. Abakumov,
• Alevtina S. Semkina and
• Alexander G. Mazhuga

Beilstein J. Nanotechnol. 2019, 10, 1964–1972, doi:10.3762/bjnano.10.193

• a spherical shape of the nanoparticles with an average diameter of 5–8 nm and a cubic spinel-type crystal structure of space group Fd−3m. Raman, Mössbauer and NMR spectroscopy clearly indicate the presence of the maghemite γ-Fe2O3 phase. Moreover, a difference in the magnetic behavior of uncoated

• nanoparticles located inside and outside of each capsule [11] and integration of the nanoparticles in the matrix of HSA threads, as will be discussed in this paper. The problem of distinguishing between magnetite Fe3O4 and maghemite γ-Fe2O3, both of which usually appear as synthesis products of iron oxide

• of the structure due to the presence of both magnetite Fe3O4 and maghemite γ-Fe2O3. Another method to distinguish between Fe2+ and Fe3+ and their positions in the crystal structure is Mössbauer spectroscopy. However, the use of ionizing radiation and radioactive sources in this method limits the

On the relaxation time of interacting superparamagnetic nanoparticles and implications for magnetic fluid hyperthermia

• Andrei Kuncser,
• Nicusor Iacob and
• Victor E. Kuncser

Beilstein J. Nanotechnol. 2019, 10, 1280–1289, doi:10.3762/bjnano.10.127

• noninteracting particles, but in a such a way that the relaxation time will remain larger in the first case. On the contrary, Mørup et al. [31] have reported, starting from temperature-dependent Mössbauer spectroscopy data obtained on maghemite based ferrofluids, a decrease of the relaxation time with increasing

Scavenging of reactive oxygen species by phenolic compound-modified maghemite nanoparticles

• Małgorzata Świętek,
• Yi-Chin Lu,
• Rafał Konefał,
• Liliana P. Ferreira,
• M. Margarida Cruz,
• Yunn-Hwa Ma and
• Daniel Horák

Beilstein J. Nanotechnol. 2019, 10, 1073–1088, doi:10.3762/bjnano.10.108

• Abstract Maghemite (γ-Fe2O3) nanoparticles obtained through co-precipitation and oxidation were coated with heparin (Hep) to yield γ-Fe2O3@Hep, and subsequently with chitosan that was modified with different phenolic compounds, including gallic acid (CS-G), hydroquinone (CS-H), and phloroglucinol (CS-P

• . In conclusion, the high cellular uptake and the antioxidant properties associated with the phenolic moieties in the modified particles allow for a potential application in biomedical areas. Keywords: antioxidants; chitosan; maghemite nanoparticles; oxidative stress; phenolic compound; Introduction

• functional groups. In this study, magnetite (Fe3O4) nanoparticles were synthetized by coprecipitation of iron(II) chloride and iron(III) chloride with ammonia and subsequently oxidized with hydrogen peroxide under mild acidic conditions. The resulting maghemite (γ-Fe2O3) has the benefit of higher chemical

Tungsten disulfide-based nanocomposites for photothermal therapy

• Tzuriel Levin,
• Hagit Sade,
• Rina Ben-Shabbat Binyamini,
• Maayan Pour,
• Iftach Nachman and
• Jean-Paul Lellouche

Beilstein J. Nanotechnol. 2019, 10, 811–822, doi:10.3762/bjnano.10.81

• for the targeted treatment of cancer, in which a light-responsive material is irradiated with a laser in the near-infrared range. In the current article we present WS2 nanotubes functionalized with previously reported ceric ammonium nitrate–maghemite (CAN-mag) nanoparticles, used for PTT

• magnetite nanoparticles into γ-maghemite (mag) nanoparticles. The cerium ion attaches to the nanoparticle, producing surface defects (an Fe–O–[CeLn] bond is formed). The cerium-doped maghemite nanoparticles are more stable than the non-doped ones, which tend to aggregate. In addition to the stabilization

• nanoparticles were washed with three portions of ddH2O (40 mL each) to neutrality. Then, ddH2O (30 mL) was added, and the maghemite NPs suspension was set aside for a minimum of 1.5 h at ambient temperature for aging, before any further use. A solution of CAN (500.0 mg, 0.912 mmol) in acetone (6.0 mL) was added

Size-selected Fe₃O₄–Au hybrid nanoparticles for improved magnetism-based theranostics

• Maria V. Efremova,
• Yulia A. Nalench,
• Eirini Myrovali,
• Anastasiia S. Garanina,
• Ivan S. Grebennikov,
• Polina K. Gifer,
• Maxim A. Abakumov,
• Marina Spasova,
• Makis Angelakeris,
• Alexander G. Savchenko,
• Michael Farle,
• Natalia L. Klyachko,
• Alexander G. Majouga and
• Ulf Wiedwald

Beilstein J. Nanotechnol. 2018, 9, 2684–2699, doi:10.3762/bjnano.9.251

• -dependent study of hybrid Fe3O4–Au NPs with Janus structure for application in theranostics where improvements in MRI and MPH were demonstrated. Increasing the magnetic NP diameter from 6 to 44 nm, we show the gradual transition of their lattice parameters from an intermediate value between maghemite γ

• . Since magnetite (Fe3O4) and maghemite (γ-Fe2O3) are structurally similar, XRD alone does not provide an accurate discrimination between the two phases. As listed in Table 1, the lattice parameter approaches bulk Fe3O4 (a = 0.8397 nm) rather than bulk γ-Fe2O3 (a = 0.8347 nm) with increasing NP size [31

• presented in Table 2. XRD and AES data for the samples MNP-15, MNP-25 and MNP-44 correlate well within 3%. The larger difference for MNP-6 can be explained by the presumably larger fraction of maghemite in this sample. For all further analysis we use the AES results. Magnetic properties The static magnetic

Cytotoxicity of doxorubicin-conjugated poly[N-(2-hydroxypropyl)methacrylamide]-modified γ-Fe₂O₃ nanoparticles towards human tumor cells

• Zdeněk Plichta,
• Yulia Kozak,
• Rostyslav Panchuk,
• Viktoria Sokolova,
• Matthias Epple,
• Lesya Kobylinska,
• Pavla Jendelová and
• Daniel Horák

Beilstein J. Nanotechnol. 2018, 9, 2533–2545, doi:10.3762/bjnano.9.236

• -Dichloroethane (DCE), hydrazine hydrate, ethanol (99.8%), and other chemicals were purchased from Sigma-Aldrich or Lach-Ner (Neratovice, Czech Republic) and used as received. N-(2-hydroxypropyl)methacrylamide (HPMA) and citrate-stabilized maghemite (γ-Fe2O3) were synthetized according to earlier procedures [16

• , since they yield hydrophilic particles that are mildly polydisperse and do not need any transfer in water. The advantage of maghemite over magnetite consists in its chemical stability [22]. Moreover, the particles exhibited superparamagnetic behavior as documented in our previous paper [23]. This

• using a magnetic field allowing for easy separation and/or targeted delivery in the organism [26]. In this report, citrate-treated maghemite nanoparticles and a novel PHPMA-based surface coating were used to ensure biocompatibility, minimal immunogenicity and to provide reactive functional groups for

Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations

• Jaison Jeevanandam,
• Ahmed Barhoum,
• Yen S. Chan,
• Alain Dufresne and
• Michael K. Danquah

Beilstein J. Nanotechnol. 2018, 9, 1050–1074, doi:10.3762/bjnano.9.98

• ]. Generally, biocompatible magnetite (Fe3O4), iron oxide, iron sulfides and maghemite (Fe2O3) are synthesized using magnetotactic bacteria [156][157] that helps in targeted cancer treatment via magnetic hyperthermia, magnetic resonance imaging (MRI), DNA analysis and gene therapy [158]. Moreover, surface

Heavy-metal detectors based on modified ferrite nanoparticles

• Urszula Klekotka,
• Ewelina Wińska,
• Elżbieta Zambrzycka-Szelewa,
• Dariusz Satuła and
• Beata Kalska-Szostko

Beilstein J. Nanotechnol. 2018, 9, 762–770, doi:10.3762/bjnano.9.69

• at 650–590 cm−1 are typical for Fe–O in magnetite/maghemite [32]. This observation confirms a successful modification of the surface of the nanoparticles. The spectra in Figure 4B were collected after the exposition of nanoparticles modified with SA to Cd, Cu and Pb ions. As a result, signals in the

• attachment) powdered samples of nanoparticles were analyzed using Raman spectroscopy giving additional information to IR spectroscopy. In Figure 5 selected spectra are presented. The Raman spectra show a set of peaks that are typical for inorganic cores (magnetite, maghemite/hematite) with accordingly

• modified organic shells. In Figure 5A only spectra of unmodified particles are collected. One can see that these spectra are dominated by signals centered around 600–700 cm−1. This signal can be attributed both to magnetite and maghemite. The position closer to the middle value of 673–683 cm−1 suggests a

Anchoring Fe₃O₄ nanoparticles in a reduced graphene oxide aerogel matrix via polydopamine coating

• Błażej Scheibe,
• Radosław Mrówczyński,
• Natalia Michalak,
• Karol Załęski,
• Michał Matczak,
• Mateusz Kempiński,
• Zuzanna Pietralik,
• Mikołaj Lewandowski,
• Stefan Jurga and
• Feliks Stobiecki

Beilstein J. Nanotechnol. 2018, 9, 591–601, doi:10.3762/bjnano.9.55

• (Fe3O4) or maghemite (γ-Fe2O3), are common functional additives widely applied in many different branches of science [35][36]. This is mainly thanks to their low price, simplicity of production, biocompatibility and environmental friendliness. There are two commonly used methods of iron oxide MNPs

Involvement of two uptake mechanisms of gold and iron oxide nanoparticles in a co-exposure scenario using mouse macrophages

• Dimitri Vanhecke,
• Dagmar A. Kuhn,
• Dorleta Jimenez de Aberasturi,
• Sandor Balog,
• Ana Milosevic,
• Dominic Urban,
• Diana Peckys,
• Niels de Jonge,
• Wolfgang J. Parak,
• Alke Petri-Fink and
• Barbara Rothen-Rutishauser

Beilstein J. Nanotechnol. 2017, 8, 2396–2409, doi:10.3762/bjnano.8.239

• ][45], and characterisation are provided in Supporting Information File 1 (Figures S1–S13). Please note that the synthesis protocol employed for the iron oxide NPs has been reported to yield maghemite (γ-Fe2O3), but as no experimental verification was applied to exclude formation of magnetite (Fe3O4

Characterization of ferrite nanoparticles for preparation of biocomposites

• Urszula Klekotka,
• Magdalena Rogowska,
• Dariusz Satuła and
• Beata Kalska-Szostko

Beilstein J. Nanotechnol. 2017, 8, 1257–1265, doi:10.3762/bjnano.8.127

• ], it was expected that the crystal structure of magnetite/maghemite would remain unchanged and the Me ions would relocate rather randomly in the Fe crystallographic positions. There are no traces of any crystalline separation which would be observed as extra diffraction peaks. Therefore, it is

• way, and thereby the value of the calculated average particle size (which appears smaller than it is in reality) [21]. But even so, the correlation between TEM and XRD is satisfactory. The X-ray spectra presented in Figure 3 show that hkl indexes in every spectra are typical for magnetite/maghemite

Photocatalysis applications of some hybrid polymeric composites incorporating TiO₂ nanoparticles and their combinations with SiO₂/Fe₂O₃

• Andreea Laura Chibac,
• Tinca Buruiana,
• Violeta Melinte and
• Emil C. Buruiana

Beilstein J. Nanotechnol. 2017, 8, 272–286, doi:10.3762/bjnano.8.30

• nanocatalysts. Keywords: hybrid polymer composites; maghemite nanoparticles; photocatalysis; TiO2 nanoparticles; UV–visible irradiation; Introduction Over the last years, titania nanomaterials have attracted a lot of attention as they have found numerous applications in the field of dye-sensitized solar cells

• , namely: nanocrystalline TiO2, TiO2 with Si–O–Si sequences (TiO2/SiO2), TiO2 with maghemite nanoparticles (TiO2/Fe2O3), and TiO2 with Si–O–Si and maghemite (TiO2/SiO2/Fe2O3). For the preparation of these composites premade nanoparticles were dispersed into urethane dimethacrylate followed by

• to the Scherrer equation is about 12.8 nm. The TEM image evidenced the association of small nanoparticles (10–20 nm) with Si–O–Si linkages to form larger structures of about 150–250 nm. The XRD pattern of the mixture TiO2 NPs/maghemite (Figure 1c) contains mainly the diffraction peaks specific to

From iron coordination compounds to metal oxide nanoparticles

• Mihail Iacob,
• Carmen Racles,
• Codrin Tugui,
• George Stiubianu,
• Adrian Bele,
• Liviu Sacarescu,
• Daniel Timpu and
• Maria Cazacu

Beilstein J. Nanotechnol. 2016, 7, 2074–2087, doi:10.3762/bjnano.7.198

• present any peaks, indicating that both samples are amorphous, while the diffractogram of sample NPT2 (Supporting Information File 1, Figure S9) shows diffraction peaks, which coincide with those from the JCPDS 04-0755 database and are characteristic for maghemite (γ-Fe2O3). The morphology of the