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

• , for the first time, the effect of pH on the magnetic-field-assisted synthesis of iron oxide nanoparticles was investigated. The results show that different nanostructures were formed upon varying the initial pH of the reaction mixture: spheres were obtained at a highly alkaline pH whereas rods were

• these nanocrystals still persists in the reaction products. Results and Discussion Main synthetic routes The effect of pH on the magnetic-field-assisted synthesis of iron oxide nanoparticles was studied by adding 2 mL of the iron ion solution (1 M FeCl3 and 0.5 M FeSO4 in 0.1 M HCl) to 5 mL of NaOH

• diffraction patterns were performed using Origin 8.5. To calculate the area and FWHM, the peaks were fitted by Gaussian functions. Raman spectroscopy The crystalline structure and phase composition of the iron oxide nanoparticles were investigated using a Horiba Jobin Yvon micro-Raman spectrometer (LabRam

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

• synthesized in small dimensions, which ensures low toxicity and the possibility for easy surface functionalization. A common method for synthesising iron-oxide nanoparticles includes chemical co-precipitation, which involves the simultaneous precipitation of magnetic nanoparticles and a solid matrix through a

• corresponding magnetic configuration of the system. For the numerical simulation, two widely known models have been used [19][20][21]. We started with a system of single-domain magnetic nanoparticles, consisting of spherical iron-oxide nanoparticles with uniaxial magnetic anisotropy, which have a lognormal

• direction connecting the i-th and j-th particles, Dij is the distance between the centres of the i-th and j-th nanoparticles, sij = Dij – (ri + rj) is the surface-to-surface separation between the i-th and j-th nanoparticles, and Aeff is the Hamaker effective constant for iron-oxide nanoparticles in water

Photothermally active nanoparticles as a promising tool for eliminating bacteria and biofilms

• Mykola Borzenkov,
• Piersandro Pallavicini,
• Angelo Taglietti,
• Laura D’Alfonso,
• Maddalena Collini and
• Giuseppe Chirico

Beilstein J. Nanotechnol. 2020, 11, 1134–1146, doi:10.3762/bjnano.11.98

• ]. Functionalized iron oxide nanoparticles can also be used for photothermally induced bacteria eradication. It was demonstrated that the NIR-absorbing nanoparticles functionalized with recyclable iron oxide were capable of eliminating Gram-positive (S. aureus) and Gram-negative bacteria (E. coli) quickly and

• effectively [94]. To this end, iron oxide nanoparticles were coated with catechol-conjugated poly(vinylpyrrolidone) sulfobetaine and then self-assembled with poly(3,4-ethylenedioxythiophene). The latter polymer is capable of absorbing NIR light while capturing the bacteria, effectively releasing heat under

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

• .11.94 Abstract Superparamagnetic iron oxide nanoparticles (SPIONs) have unique properties with regard to biological and medical applications. SPIONs have been used in clinical settings although their safety of use remains unclear due to the great differences in their structure and in intra- and inter

• therapeutic efficacy, and safety studies. Keywords: drug delivery; drug targeting; endocytosis; medical; nanoparticles; superparamagnetic iron oxide nanoparticles (SPIONs); toxicity; Introduction Nanoencapsulation technologies have been researched over the past several decades and have been widely

• microscopy (EM), iron oxide magnetic beads for the separation of cells and molecules, gold and silver nanoparticles as fiducials for EM, for immuno-EM labeling and surface-enhanced Raman spectroscopy, or for gene transfection, liposomes for drug delivery, and gadolinium or iron oxide nanoparticles for

Wet-spinning of magneto-responsive helical chitosan microfibers

• Dorothea Brüggemann,
• Johanna Michel,
• Naiana Suter,
• Matheus Grande de Aguiar and
• Michael Maas

Beilstein J. Nanotechnol. 2020, 11, 991–999, doi:10.3762/bjnano.11.83

• neodymium magnet (see Supporting Information File 2 for the full video). Scheme of the wet-spinning process that generated helical microfibers. A solution of chitosan and magnetic iron oxide nanoparticles was extruded into an ethanol coagulation bath. The emerging fibers were collected by a teflon-coated

• oxide nanoparticles in order to generate 3D spheroids [43][44][45][46]. The production of helical microfibers can, in principle, be achieved by adding a rotation element to the translational extrusion process. This has been demonstrated by Sun et al. who developed a magnetic micromanipulation technique

• cell behavior in vivo by applying external stimuli [41][42]. Emerging fields, such as magnetic tissue engineering, which uses magnetic levitation to control cell growth, would greatly benefit from the use of magnetic scaffolds since these would replace the need for treating the cells with magnetic iron

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

• nanoparticles (AuNPs); blood–brain barrier (BBB); drug delivery; liposomes; nanomedicine; polymeric nanoparticles; solid lipid nanoparticles; superparamagnetic iron oxide nanoparticles (SPIONs); Introduction Neurological disorders and brain diseases are real burdens for modern societies and healthcare systems

• (e.g., human serum albumin) [28], gold nanoparticles [29] and superparamagnetic iron oxide nanoparticles [30]. This review aims to summarize (i) the different pathways to cross the BBB, (ii) the strategies that can be employed to increase nanoparticle BBB permeation without disrupting the BBB, as well

• in non-neurogenic regions. Disruption of the BBB by NIR light irradiation of AuNRs increased the AuNRs ability to accumulate in the SVZ, making this formulation interesting for targeting neural stem cells. Superparamagnetic iron oxide nanoparticles: Superparamagnetic iron oxide nanoparticles (SPIONs

Luminescent gold nanoclusters for bioimaging applications

• Nonappa

Beilstein J. Nanotechnol. 2020, 11, 533–546, doi:10.3762/bjnano.11.42

• –nanocluster agglomerates as luminescent nanocarriers for imaging and combination therapy [89][90]. Core–shell nanoparticles consisting of oleic acid-capped superparamagnetic iron oxide nanoparticles (IONPs, d = 6.7 ± 1.2 nm) were used (Figure 5A). The IONPs were subsequently coated with a gold shell using the

Understanding nanoparticle flow with a new in vitro experimental and computational approach using hydrogel channels

• Armel Boutchuen,
• Dell Zimmerman,
• Abdollah Arabshahi,
• John Melnyczuk and
• Soubantika Palchoudhury

Beilstein J. Nanotechnol. 2020, 11, 296–309, doi:10.3762/bjnano.11.22

• highlights the reliability of our new in vitro technique in providing mechanistic insights of NP flow for potential preclinical stage applications. Keywords: computational fluid dynamics; drug delivery; iron oxide nanoparticles; nanoparticle flow; poly(hydroxyethyl methacrylate) (pHEMA) hydrogels

• . Characterization of iron oxide nanoparticles A Litesizer 500 (Anton Paar) particle analyzer equipped with zeta potential capability was used to measure the hydrodynamic size, stability, and surface charge of aqueous dispersions of iron oxide NPs at pH 7 at room temperature (Figure S4, Supporting Information File 1

• hood for 12 h to form the different hydrogels. The hydrogels were subsequently characterized via swelling studies and SEM to find the best suitable soft material for fabrication of flow paths that mimic physiologically relevant properties in terms of flexibility and smoothness. Synthesis of iron oxide

Molecular architectonics of DNA for functional nanoarchitectures

• Debasis Ghosh,
• Lakshmi P. Datta and
• Thimmaiah Govindaraju

Beilstein J. Nanotechnol. 2020, 11, 124–140, doi:10.3762/bjnano.11.11

• using three 55 nucleotide-long carboxylic acid-linked DNA strands and a tumor-targeting 87 nucleotide-long aptamer. The carboxylic acid groups of the DNA tetrahedron facilitated the interaction with oleic acid-coated iron oxide nanoparticles via a ligand exchange reaction. The aptamer–DNA tetrahedron

Dynamics of superparamagnetic nanoparticles in viscous liquids in rotating magnetic fields

• Nikolai A. Usov,
• Ruslan A. Rytov and
• Vasiliy A. Bautin

Beilstein J. Nanotechnol. 2019, 10, 2294–2303, doi:10.3762/bjnano.10.221

• ; viscous liquid; Introduction Magnetic nanoparticles are promising materials in various areas of biomedicine [1][2][3][4], such as magnetic resonance imaging [5][6][7], targeted drug delivery [8][9][10], and magnetic hyperthermia [11][12][13][14][15][16][17][18][19][20]. Iron oxide nanoparticles are most

• of particle diameters where the SAR in RMFs has a maximum. This behavior of the SAR in RMFs resembles the one in AMFs, [11][25]. For iron oxide nanoparticles of optimal diameter the SAR in RMFs reaches values of the order of 400–450 W/g at a frequency f = 400 kHz and moderate amplitude H0 = 100 Oe

• a frequency f = 400 kHz and a moderate amplitude H0 = 100 Oe. Nevertheless, the experimentally measured [41][43] SAR values in RMFs for an assembly of iron oxide nanoparticles distributed in a viscous liquid turned out to be very small, only about 1.0–4.0 W/g. This may be due to the small RMF

Targeted therapeutic effect against the breast cancer cell line MCF-7 with a CuFe₂O₄/silica/cisplatin nanocomposite formulation

• B. Rabindran Jermy,
• Vijaya Ravinayagam,
• Widyan A. Alamoudi,
• Dana Almohazey,
• Hatim Dafalla,
• Lina Hussain Allehaibi,
• Abdulhadi Baykal,
• Muhammet S. Toprak and
• Thirunavukkarasu Somanathan

Beilstein J. Nanotechnol. 2019, 10, 2217–2228, doi:10.3762/bjnano.10.214

• (magnetic resonance imaging), tissue repair, and thermal ablation have been gaining considerable attention in recent years. In particular, the use of superparamagnetic iron oxide nanoparticles (SPIONs) is now advantageous as they are FDA-approved for clinical use [2]. Magnetic Fe3O4-based mesoporous silica

Use of data processing for rapid detection of the prostate-specific antigen biomarker using immunomagnetic sandwich-type sensors

• Camila A. Proença,
• Tayane A. Freitas,
• Thaísa A. Baldo,
• Elsa M. Materón,
• Flávio M. Shimizu,
• Gabriella R. Ferreira,
• Frederico L. F. Soares,
• Ronaldo C. Faria and
• Osvaldo N. Oliveira Jr.

Beilstein J. Nanotechnol. 2019, 10, 2171–2181, doi:10.3762/bjnano.10.210

• magnetism than other iron oxide nanoparticles [17]. These MNPs can be synthesized through various techniques, such as ultrasound irradiation, sol–gel methods, thermal decomposition, and co-precipitation [18][19][20][21]. In addition, they can be modified with biomolecules and other compounds to improve the

• carbon electrodes (INμ-SPCEs) showed limits of detection of 0.23 pg·mL−1 for PSA and 0.30 pg·mL−1 for IL-6, measured in the serum of prostate cancer patients [26]. Immunosensors to detect PSA include magnetic nanoparticles modified with gold [27], nitrodopamine functionalized iron oxide nanoparticles [3

• immunoassays for the detection of PSA. Supporting Information Supporting Information features detailed information on the synthesis of magnetic iron oxide nanoparticles, electrode fabrication, and sample preparation. Also, the characterization of MNPs and electrode surfaces by using Fourier-transform infrared

Nitrogen-vacancy centers in diamond for nanoscale magnetic resonance imaging applications

• Alberto Boretti,
• Lorenzo Rosa,
• Jonathan Blackledge and
• Stefania Castelletto

Beilstein J. Nanotechnol. 2019, 10, 2128–2151, doi:10.3762/bjnano.10.207

• NV magnetometer and the related MRI contrast. MRI contrast is thus correlated to submicrometer resolution and nanotesla sensitivity magnetic field measurements in biological samples. Molecular-imaging agents such as iron oxide nanoparticles (IONPs) can strongly influence MRI images with their

• monitoring intracellular processes relevant in biological and medical applications. In this context, hybrid systems using NV sensors with other MRI contrast agents or sensors have been proposed such as iron oxide nanoparticles and paramagnetic gadolinium complexes. SPIONs are single-domain magnetic systems

Microbubbles decorated with dendronized magnetic nanoparticles for biomedical imaging: effective stabilization via fluorous interactions

• Da Shi,
• Justine Wallyn,
• Dinh-Vu Nguyen,
• Francis Perton,
• Delphine Felder-Flesch,
• Sylvie Bégin-Colin,
• Mounir Maaloum and
• Marie Pierre Krafft

Beilstein J. Nanotechnol. 2019, 10, 2103–2115, doi:10.3762/bjnano.10.205

• ), were synthesized and grafted on the surface of iron oxide nanoparticles (IONPs) for microbubble-mediated imaging and therapeutic purposes. The size and stability of the dendronized IONPs (IONP@CnX2n+1OEG8Den) in aqueous dispersions were monitored by dynamic light scattering. The investigation of the

• the phospholipid film, while those grafted with the hydrocarbon dendrons are located at the surface of the phospholipid film. Keywords: diagnostic imaging; fluorinated dendrons; fluorocarbon; iron oxide nanoparticles; magnetic nanoparticles; microbubbles; Introduction Microbubbles (MBs), that is

• signal for energy deposition, as is required for sonothrombolysis or ablation surgery. MBs incorporating iron oxide nanoparticles (IONPs) are sought after as dual contrast agents for ultrasound and magnetic resonance imaging [18][19][20] and drug delivery [21][22]. The shells of the presently available

Gold-coated plant virus as computed tomography imaging contrast agent

• Alaa A. A. Aljabali,
• Mazhar S. Al Zoubi,
• Khalid M. Al-Batanyeh,
• Ali Al-Radaideh,
• Mohammad A. Obeid,
• Abeer Al Sharabi,
• Walhan Alshaer,
• Bayan AbuFares,
• Tasnim Al-Zanati,
• Murtaza M. Tambuwala,
• Naveed Akbar and
• David J. Evans

Beilstein J. Nanotechnol. 2019, 10, 1983–1993, doi:10.3762/bjnano.10.195

• contrast. This effect is known as paramagnetic relaxation enhancement [2] and is common among contrast agents containing gadolinium [3] and iron oxide nanoparticles [4]. CT is a non-invasive, diagnostic imaging tool that allows for 3-D visual reconstruction and tissue segmentation. It relies on the use of

Porous silver-coated pNIPAM-co-AAc hydrogel nanocapsules

• William W. Bryan,
• Riddhiman Medhi,
• Maria D. Marquez,
• Supparesk Rittikulsittichai,
• Michael Tran and
• T. Randall Lee

Beilstein J. Nanotechnol. 2019, 10, 1973–1982, doi:10.3762/bjnano.10.194

• , Zhao et al. created pH- and temperature-sensitive bioprobes by incorporating pNIPAM hydrogel cores with europium organic complexes [67]. In separate studies, Lee and co-workers utilized both biocompatible gold nanoshells, iron oxide nanoparticles, and gold nanorods with thermo-responsive hydrogel

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

• and human serum albumin coated iron oxide nanoparticles was observed by Mössbauer spectroscopy. Conclusion: This difference in magnetic behavior is explained by the influence of biofunctionalization on the magnetic and electronic properties of the iron oxide nanoparticles. The ZF-NMR spectra analysis

• allowed us to determine the relative amount of iron located in the core and the surface layer of the nanoparticles. The obtained results are important for understanding the structural and magnetic properties of iron oxide nanoparticles used as T2 contrast agents for MRI. Keywords: iron oxides; Mössbauer

• 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

Engineered superparamagnetic iron oxide nanoparticles (SPIONs) for dual-modality imaging of intracranial glioblastoma via EGFRvIII targeting

• Xianping Liu,
• Chengjuan Du,
• Haichun Li,
• Ting Jiang,
• Zimiao Luo,
• Zhiqing Pang,
• Daoying Geng and
• Jun Zhang

Beilstein J. Nanotechnol. 2019, 10, 1860–1872, doi:10.3762/bjnano.10.181

• Education, 826 Zhangheng Road, Shanghai 201203, China 10.3762/bjnano.10.181 Abstract In this work, a peptide-modified, biodegradable, nontoxic, brain-tumor-targeting nanoprobe based on superparamagnetic iron oxide nanoparticles (SPIONs) (which have been commonly used as T2-weighted magnetic resonance (MR

• imaging (MRI); molecular imaging; superparamagnetic iron oxide nanoparticles (SPIONs); nanomedicine; tumor resection; Introduction Tumor resection is one of the most promising clinical treatments of glioblastoma, which is commonly associated with high mortality and inevitable tumor recurrence. To achieve

• , gadolinium (Gd)-based agents (often Gd-diethylenetriaminepentaacetic acid (DTPA)) and superparamagnetic iron oxide nanoparticles (SPIONs) are the paramagnetic materials generally used as contrast agents to impact the relaxation time T1 or T2, thus generating bright or dark images via MR imaging. Gd-DTPA, as

Photoactive nanoarchitectures based on clays incorporating TiO₂ and ZnO nanoparticles

• Eduardo Ruiz-Hitzky,
• Pilar Aranda,
• Marwa Akkari,
• Nithima Khaorapapong and
• Makoto Ogawa

Beilstein J. Nanotechnol. 2019, 10, 1140–1156, doi:10.3762/bjnano.10.114

• ][132]. The incorporation of various types of NPs using neat clay and applying a two-step synthesis has been reported. A recent example of this refers to the incorporation of ZnO nanoparticles to a Fe3O4-sepiolite nanoarchitecture previously prepared by in situ formation of superparamagnetic iron-oxide

• nanoparticles on the external surface of sepiolite fibres. The resulting ZnO–Fe3O4@sepiolite nanoarchitecture exhibits photoactivity due to the ZnO NPs, and the presence of magnetite NPs facilitates the recovery by the use of a magnet (Figure 4) [133]. Moreover, the presence of iron oxide could be useful also

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

• conjugation via esterification or amidation, and free-radical grafting [16]. The aim of this work was to design and fabricate superparamagnetic iron oxide nanoparticles with antioxidant properties. Positively charged γ-Fe2O3 nanoparticles were synthesized through co-precipitation, and their surface was

• induce oxidative stress in living organisms via the Fenton reaction. Therefore, it is crucially important in biological applications of iron oxide nanoparticles to counteract this undesirable effect by antioxidants. The combination of magnetic targetability with antioxidant properties is an interesting

Influence of dielectric layer thickness and roughness on topographic effects in magnetic force microscopy

• Alexander Krivcov,
• Jasmin Ehrler,
• Marc Fuhrmann,
• Tanja Junkers and
• Hildegard Möbius

Beilstein J. Nanotechnol. 2019, 10, 1056–1064, doi:10.3762/bjnano.10.106

• overlapped by additional forces acting on the tip such as electrostatic forces. In this work the possibility to reduce capacitive coupling effects between tip and substrate is discussed in relation to the thickness of a dielectric layer introduced in the system. Single superparamagnetic iron oxide

• nanoparticles (SPIONs) are used as a model system, because their magnetic signal is contrariwise to the signal due to capacitive coupling so that it is possible to distinguish between magnetic and electric force contributions. Introducing a dielectric layer between substrate and nanoparticle the capacitive

Magnetic field-assisted assembly of iron oxide mesocrystals: a matter of nanoparticle shape and magnetic anisotropy

• Julian J. Brunner,
• Marina Krumova,
• Helmut Cölfen and
• Elena V. Sturm (née Rosseeva)

Beilstein J. Nanotechnol. 2019, 10, 894–900, doi:10.3762/bjnano.10.90

• presented a way to form “directed mesocrystals” from superparamagnetic iron oxide nanoparticles using a homogeneous magnetic field. These directed mesocrystals are elongated along the magnetic field and their structure differs from regular self-assembled mesocrystals produced under the same conditions but

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

• magnetic field until it approaches saturation, and there is no hysteresis loop. Superparamagnetism is typical for iron-oxide nanoparticles [67]. The nanocomposite WS2-NT-CM (blue curve) maintains superparamagnetism, with a saturation value of about ±13 emu/g, which is a sixth of the saturation value for

Heating ability of magnetic nanoparticles with cubic and combined anisotropy

• Nikolai A. Usov,
• Mikhail S. Nesmeyanov,
• Elizaveta M. Gubanova and
• Natalia B. Epshtein

Beilstein J. Nanotechnol. 2019, 10, 305–314, doi:10.3762/bjnano.10.29

• ; Introduction Magnetic hyperthermia [1][2][3] is a promising therapeutic method that can be used in combination with chemotherapy or radiotherapy for cancer treatment. Iron oxide nanoparticles are among the materials most popular for application in biomedicine due to their biocompatibility, biodegradability [4

• ] have been devoted to the development of advanced methods for the synthesis of iron oxide nanoparticles and measurement of their SAR under various conditions. It should be noted that in theoretical SAR calculations [15][16][17][18][19][20][21][22] the assemblies of magnetic nanoparticles with uniaxial

• magnetic anisotropy have mostly been studied. Meanwhile, perfect iron oxide nanoparticles of spherical shape should have cubic-type magnetic anisotropy [5]. However, to describe the existing experimental data properly one has also to take into account the possible perturbation of the nanoparticle shape. A

Wet chemistry route for the decoration of carbon nanotubes with iron oxide nanoparticles for gas sensing

• Hussam M. Elnabawy,
• Juan Casanova-Chafer,
• Badawi Anis,
• Mostafa Fedawy,
• Mattia Scardamaglia,
• Carla Bittencourt,
• Ahmed S. G. Khalil,
• Eduard Llobet and
• Xavier Vilanova

Beilstein J. Nanotechnol. 2019, 10, 105–118, doi:10.3762/bjnano.10.10

• , 7000 Mons, Belgium Physics Department & Center for Environmental and Smart Technology (CEST), Faculty of Science, Fayoum University, Fayoum, Egypt 10.3762/bjnano.10.10 Abstract In this work, we investigated the parameters for decorating multiwalled carbon nanotubes with iron oxide nanoparticles using

• with iron oxide nanoparticles substantially ameliorated the response towards nitrogen dioxide. Keywords: benzene detection; doping; gas sensor; metal nanoparticle decoration; multiwalled carbon nanotubes; NO2 detection; room temperature gas sensing; surface modification; Introduction Carbon nanotubes

• ) well below air quality guidelines [24][25], which indicates the importance of fabricating such a gas sensor to be used in different applications. In this paper, we report on a wet chemistry route that was successfully employed to chemically modify CNTs by decorating them with iron oxide nanoparticles